Document:

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                                                                    EXHIBIT 10.5

                                                           (English Translation)

                    POLYCRYSTALLINE SILICON SUPPLY AGREEMENT

Party A:       Canadian Solar Inc.
Address:       Mississauga, Ontario, Canada

Party B:       Luoyang Zhong Gui High-Tech Co., Ltd.
Address:       Yanshi City, Luoyang, Henan Province, China

Whereas:

1.    Party A intends to invest in and form a silicon solar cell or panel
      component company in Luoyang;

2.    Party B agrees to supply polycrystalline silicon products to Party A after
      the polycrystalline production commences and achieves a certain production
      capacity; after friendly discussion, Party A and Party B hereby reach the
      following agreement on Party B's supply of polycrystalline silicon to
      Party A:

Article 1      Product Supply

Party B agrees to supply polycrystalline silicon products ("Products") to Party
A according to this Agreement in such quantity as determined in accordance with
the relevant provisions of this Agreement.

Party A will carry out the actual procurement through a wholly-owned subsidiary
in China designated by Party A.

Article 2      Quantity of Supply

<TABLE>
<CAPTION>
         Year   Quantity
         ----   --------
<S>      <C>    <C>
1        2006   No less than 50 tons (to be supplied in equal monthly quantity in principle)

2        2007   No less than 50 tons

3        2008   If Phase II Expansion proceeds as scheduled, no less than 300 tons; if it does not proceed as
                scheduled, no less than 50 tons.

4        2009   If Phase II Expansion proceeds as scheduled, no less than 400 tons; if it does not proceed as
                scheduled, no less than 50 tons.

5        2010   If Phase II Expansion proceeds as scheduled, no less than 500 tons; if it does not proceed as
                scheduled, no less than 100 tons.
</TABLE>

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Article 3      Supply Undertaking

Party B undertakes to begin delivery to Party A no later than February 2006.

1.  On the basis of same quality and same price, Party B will supply the
    Products to Party A in priority except it will first satisfy the needs of
    such other entities as Luoyang Monocrystalline Silicon Limited Liability
    Company for the agreed quantities.

2.  Party B agrees that the unqualified bits of material resulting in the
    course of the crushing of polycrystalline silicon will be purchased by
    Party A.

3.  Party B may unconditionally terminate this Agreement if Party A fails to
    form a silicon solar cell or panel component company in Luoyang in 2006.

Article 4      Quality Standard and Specifications

Party B shall make deliveries to Party A according to the following quality
standard and specifications:

1.  Quality Standard

    Acceptor (B): [Angle]1ppb equivalent to P type resistivity: 260 (Omega). cm.
    Donor (P):    [Angle]1ppb equivalent to N type resistivity: 43 (Omega). cm.
    Carbon (C):   [Angle]1ppma

2.  Range of size and packaging specifications: compliant with National
    Standard GB/T12963-1996 The standard Products supplied by Party B to Party
    A shall be washing free.

The above quality standard is only the reference standard for the Products to be
supplied by Party B to Party A and does not form a compulsory production
standard for the quality of Party B's products. Party A will accept the
non-washing free products of Party B in other specifications.

Article 5      Principle for Determination of Supply Price and Payment

1.  The price of the Products to be supplied by Party B to Party A: subject to
    the same quality standard, the price of the Products shall be determined
    by Party A and Party B on the basis of the market price in accordance with
    Article 6 hereof.

2.  When the market price changes, the supply price shall be adjusted by the
    Parties on the basis of the changed market price in the first month of the
    quarter in which the change occurs; if the change of the market price does
    not occur in the first month of the quarter, the adjustment shall be made
    by the Parties on the basis of the changed market price in the first month
    of the next

                                      -2-

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      quarter. The price of the Products shall remain unchanged for one quarter
      after such price adjustment.

3.    Party A agrees to make an advance payment of RMB30 million Yuan for the
      product price to Party B in three installments after this Agreement duly
      comes into effect:

      (1)   RMB10 million Yuan within 7 days after this Agreement duly comes
            into effect;

      (2)   Party A will pay RMB10 million Yuan to Party B within 7 days after
            the first furnace in Party B's production line has successfully
            completed the first heat; Party B shall notify Party A one week in
            advance according to its funding need;

      (3)   Party A will pay RMB10 million Yuan to Party B within one month
            after all six furnaces of Party B have successfully completed the
            first heat.

4.    Party A shall pay 30% of the product price in advance within one week of
      receipt of the delivery notice from Party B, and the remaining 70% of the
      product price shall be deducted from the advance payment of Party A.

5.    Party A agrees to make an advance payment of RMB30 million Yuan each year
      into Party B's account as requested by Party B at any time in 2007 and
      2008; subject to this condition, the payment of the product price by Party
      A to Party B will be discussed separately.

Article 6      Procedure of Supply

1.    Party A and Party B shall agree in writing on the material terms of the
      supply, such as the price of the Products, quantity, quality,
      specifications and delivery schedule, under separate covers prior to each
      delivery period.

2.    Party A shall issue an order to Party B 30 days prior to a delivery
      specifying the delivery quantity, quality, specification, delivery
      schedule and current price of the Products.

3.    Upon receipt of Party A's order, Party B shall confirm the order in
      writing within 5 days. The order finally confirmed by both Parties in
      writing shall be the final basis of the supply of the Products for the
      delivery period concerned. If any Party proposes to change the delivery
      quantity or delivery time after such confirmation, that Party shall notify
      the other Party 10 days in advance and obtain the written consent of the
      other Party, otherwise it shall be liable for breach of contract.

4.    Mode of delivery: Delivery shall be taken by Party A itself according to
      the delivery date and quantity finally confirmed by the Parties and, when
      Party A takes delivery, the Parties shall confirm the quantity of the
      Product and complete the delivery formalities in writing onsite.

                                      -3-

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Article 7      Acceptance and Objection

Party A shall carry out acceptance on the very day of receipt of the Product and
shall raise any objection it may have with regard to the quality of the Product
within 30 days of delivery of the Product. If it fails to do so within this
period, it shall be deemed to have no objection.

Article 8      Liability for Breach of Contract

If any Party violates any provision of this Agreement, it shall be liable for
breach of contract accordingly. If the quality of any Product supplied by Party
B does not conform to that agreed to by the Parties, Party A has the right to
return the Products to Party B within 30 days and Party B shall promptly replace
the Products upon receipt from Party A.

The Parties agree that in the following circumstances Party A has the right to
demand the return of the advance payment:

      (1)   The Parties fail to reach an agreement on the specific price of the
            goods for a long period;

      (2)   Party B suspends production for a long period (over three months),
            becomes bankrupt or encounters other material changes;

      (3)   Party B fails to perform its obligations as required by this
            Agreement.

Article 9      Governing Law and Jurisdiction Over Disputes

1.    The conclusion, validity, interpretation and performance of and the
      resolution of disputes relating to this Agreement shall be governed by the
      laws of the mainland area of the People's Republic of China.

2.    All disputes arising from or in connection with the performance of this
      Agreement shall be resolved by the Parties through amicable consultation;
      if such consultation fails to resolve a dispute, either Party may apply to
      the Luoyang Arbitration Commission for arbitration by an arbitration
      tribunal formed by the arbitration commission in accordance with the
      arbitration rules of that arbitration commission in effect at the time of
      the application. The arbitration award shall be final and binding on both
      Parties.

Article 10     Effectiveness of Agreement

This Agreement shall come into effect after it is signed by the legal
representatives or authorized representatives of the Parties.

                                      -4-

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Article 11     Miscellaneous

This Agreement shall be written in quadruplicate with Party A and Party B each
holding two copies (including one original and one duplicate), and all four
copies of the Agreement shall have equal legal effect.

(No text of the main body hereafter)

Party A:       Canadian Solar, Inc.

               Legal representative or authorized representative: [signature]

               September 12, 2005

Party B:       Luoyang Zhong Gui  High-Tech Limited Liability Company

               Legal representative or authorized representative: [signature]

               September 11, 2005

                                      -5-<PAGE>

                                                                    EXHIBIT 10.6

                                                           (English Translation)

                   SOLAR CELL SILICON WAFER SUPPLY AGREEMENT

                                                                  CSI-LDK060602W

Party A:     Canadian Solar Inc.
Address:     Mississauga, Ontario, Canada

Party B:     Jiangxi Saiwei LDK Solar Energy High-Tech Limited Liability Company
Address:     Xinyu City High Technology Development Zone, Jiangxi Province

Whereas:

1.    Party A and Party B have friendly cooperative relationship;

2.    Party A has decided to invest in and form a solar cell silicon wafer
      production line in China;

After friendly consultation, Party A and Party B hereby reach the following
agreement on Party B's supply of polycrystalline silicon to Party A:

Article 1    Product Supply

Party B agrees to supply polycrystalline silicon wafer products ("Product") to
Party A according to this Agreement in such quantity as determined in accordance
with the relevant provisions of this Agreement.

Party A will carry out the actual procurement through its subsidiary in China
designated by it.

Article 2    Quantity of Supply

<TABLE>
<CAPTION>

                                 Quantity
                ---------------------------------------------
         Year   Quarter 1   Quarter 2   Quarter 3   Quarter 4
         ----   ---------   ---------   ---------   ---------
<S>      <C>    <C>         <C>         <C>         <C>
1        2007     1 MW        3 MW        5 MW        6 MW
2        2008                     50 MW
3        2009                     75 MW
4        2010                     108 MW
</TABLE>

<PAGE>

Article 3    Quality Standard and Specifications

Party B shall make deliveries to Party A according to its publicly announced
product quality standard and specifications.

Article 4    Principle for Determination of Supply Price and Payment

1.    The price of the Product to be supplied by Party B to Party A shall be the
      uniform price at which Party B supplies the Product to all major companies
      at that time. In principle, the price shall be determined on a monthly
      basis. Once determined, the price shall remain unchanged for at least one
      month.

2.    Party A agrees that after this Agreement duly comes into effect it will
      make an advance payment at 60% of the price to Party B as deposit six
      months before Party B begins to make deliveries, with the remaining 40% of
      the price to be paid in full within 30 days before Party B makes
      deliveries.

Article 5    Procedure of Supply

1.    Party A and Party B shall agree in writing on the material terms of the
      supply, such as the price of the Product, quantity, quality,
      specifications, delivery schedule and amount of deposit payment, under
      separate covers prior to each delivery period.

2.    Party B shall issue a supply order to Party A 45 days prior to a delivery
      specifying the delivery quantity, quality, specification and delivery
      schedule.

3.    Upon receipt of Party B's order, Party A shall confirm the supply order in
      writing within 5 days. A purchase order finally confirmed by both Parties
      in writing shall be the final basis of the supply of the Product for the
      delivery period concerned. If any Party proposes to change the delivery
      quantity or delivery time after such confirmation, that Party shall notify
      the other Party 10 days in advance and obtain the written consent of the
      other Party, otherwise it shall be liable for breach of contract
      accordingly.

4.    Mode of delivery: Delivery shall be taken by Party A itself according to
      the delivery date and quantity finally confirmed by the Parties and, when
      Party A takes delivery, the Parties shall confirm the quantity of the
      Product and complete the delivery formalities in writing onsite.

Article 7    Acceptance and Objection

Party A shall carry out acceptance on the very day of receipt of the Product and
shall raise any objection it may have with regard to the quality of the Product
within 90 days of receipt of the Product. If it fails to do so within this
period, it shall be deemed to have no objection.

                                      -2-

<PAGE>

Article 8    Liability for Breach of Contract

If any Party violates any provision of this Agreement, it shall be liable for
breach of contract accordingly. If the quality of any Product supplied by Party
B does not conform to that agreed by the Parties, Party A has the right to
return the Product to Party B within 90 days and Party B shall promptly replace
the Product upon receipt of it from Party A.

The Parties agree that in the following circumstances Party A has the right to
demand the return of the advance payment:

      (1)   Party B fails to make deliveries on schedule and according to the
            quality requirement;

      (2)   The Parties fail to reach an agreement on the specific price of the
            goods;

      (3)   Party B suspends production for a long period (over three months),
            becomes bankrupt or encounters other material changes;

      (4)   There is a material change in the equity structure of Party B or
            Party B's major shareholder;

      (5)   Party B fails to perform its obligations as required by this
            Agreement.

Party B shall return the advance payment in full within 30 days after Party A
issues a written demand for the return of the advance payment and the
obligations under this Agreement will not be deemed terminated until
confirmation is given by both Parties.

Article 9    Governing Law and Jurisdiction Over Disputes

1.    The conclusion, validity, interpretation and performance of and the
      resolution of disputes relating to this Agreement shall be governed by the
      laws of the mainland area of the People's Republic of China.

2.    All disputes arising from or in connection with the performance of this
      Agreement shall be resolved by the Parties through amicable consultation;
      if such consultation fails to resolve a dispute, either Party may apply to
      the Suzhou Contract Arbitration Commission for arbitration by an
      arbitration tribunal formed by the arbitration commission in accordance
      with the arbitration rules of that arbitration commission in effect at the
      time of the application. The arbitration award shall be final and binding
      on both Parties.

Article 10   Effectiveness of Agreement

This Agreement shall come into effect after it is signed by the legal
representatives or authorized representatives of the Parties.

                                      -3-

<PAGE>

Article 11   Miscellaneous

This Agreement shall be written in quadruplicate with Party A and Party B each
holding two copies (including one original and one duplicate), and all four
copies of the Agreement shall have equal legal effect.

                                      -4-

<PAGE>

(No text of the main body hereafter)

Party A:     Canadian Solar, Inc.

             Legal representative or authorized representative: [signature]

             July 6, 2006

Party B:     Jiangxi Saiwei LDK Solar Energy High-Tech Limited Liability Company

             Legal representative or authorized representative: [signature]

             July 6, 2006

                                      -5-

<PAGE>
                                                           (English Translation)

             SOLAR CELL SILICON WAFER SUPPLY SUPPLEMENTAL AGREEMENT

                                                               NO. 60810 CSI/LDK

Party A: Canadian Solar Inc.
Address: 4056 Jefton Crescent, Mississauga, Ontario, L5L 1Z3 Canada

Party B: Jiangxi Saiwei LDK Solar Energy High-Tech Limited Liability Company
Address: Xinyu City High Technology Development Zone, Jiangxi Province

Based on their respective developmental needs, Party A and Party B hereby
supplement the Solar Cell Silicon Wafer Supply Agreement of No. CSI-LDK060602W
that they have executed.

Party B agrees to amend the quantity of supply stipulated in the above-said
agreement as follows:

<Table>
<Caption>
                Year                           Quantity
                ----      ------------------------------------------------------
<S>             <C>       <C>            <C>            <C>            <C>

1               2007      Quarter 1      Quarter 2      Quarter 3      Quarter 4

                            1 MW           4 MW           8 MW           12 MW

2               2008                            50 MW

3               2009                            75 MW

4               2010                           108 MW

</Table>

Other provisions shall remain unchanged.

Party A:         [signature]                  Party B:        [signature]

Representative:   /s/                         Representative:  /s/
                 ----------------                             ----------------

Date:            August 11, 2006              Date:           August 11, 2006

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