<PAGE>
                                                                    EXHIBIT 16.1

                           PETROCHINA COMPANY LIMITED

                      CODE OF ETHICS FOR SENIOR MANAGEMENT

      Pursuant to the laws of the People's Republic of China (the "PRC"), the
regulatory requirements of the places where the Company is listed and the
Articles of Association of PetroChina Company Limited (hereinafter referred to
as the "Company"), the Company has adopted the following code of business
conduct and ethics for purposes of regulating the business conduct and ethics of
the senior management of the Company and protecting the Company's interests.

1.    This Code applies to all the management members of the Company, the
      general managers, deputy general managers and other senior management
      members of the same level in all departments of the Company's Headquarter,
      and those in all specialized branches, regional branches and wholly-owned
      subsidiaries of the Company (hereinafter referred to as the "Senior
      Management").

      The controlled subsidiaries of the Company shall use this Code as a
      reference in regulating the business conduct of their own senior
      management.

2.    Required Business Conduct and Ethics of the Senior Management

      (i)   THE SENIOR MANAGEMENT SHALL ACT HONESTLY AND DILIGENTLY IN THE
            PERFORMANCE OF THEIR DUTIES FOR THE COMPANY. The Senior Management
            shall establish a concept to achieve honest, innovative, productive
            and coordinative operation and management, be devoted to their
            duties and comply with their obligations diligently, use their best
            endeavors to protect the lawful rights and interests of the Company,
            and make every effort to improve the management and performance of
            the Company.

      (ii)  THE SENIOR MANAGEMENT SHALL BE PROHIBITED FROM ENGAGING IN ANY
            ACTIVITY THAT MIGHT CREATE A CONFLICT OF INTEREST WITH THE COMPANY.
            Such activities shall include:

            A.    Personal Investments. The Senior Management shall not invest
                  in any economic entity that does business with or is a
                  competitor of the Company; however, they may own less than 1%
                  of the outstanding equity securities shares of a publicly
                  traded company. A Senior Management member's spouse, children
                  or children's spouses shall not engage in any productive or
                  operational activities within the territory or of the business
                  scope managed by such Senior Management Member that may affect
                  such Senior Management member's fair and due performance of
                  duties or infringe the interests of the Company in violation
                  of relevant regulations.

                                       1
<PAGE>

            B.    Corporate Opportunities. The Senior Management are prohibited
                  from (a) taking for themselves personally opportunities that
                  are properly within the scope of the Company's activities; (b)
                  using corporate property, information or position for personal
                  gain; or (c) competing with the Company.

            C.    Business Affiliations. It is prohibited for any Senior
                  Management member to serve as a director, senior managerial
                  personnel, consultant, employee or in any other capacity in
                  any enterprise that (a) is a competitor of the Company; or (b)
                  directly interferes or has the appearance of interfering with
                  the performance of his/her duties as a Senior Management
                  member.

            D.    Business Gifts. Acceptance by the Senior Management (or their
                  parents, spouses, children or other family members sharing the
                  same residence with them or any other person with their
                  consent or under their instruction) of gifts of a value that
                  may tend to influence business decisions or compromise
                  independent judgment is prohibited. The exchange of limited
                  non-cash business courtesies by the Senior Management in
                  business activities may be acceptable, however, such exchange
                  shall not improperly influence the decisions of any business
                  partner of the Company.

            E.    Confidential Information. The Senior Management shall comply
                  with the relevant rules of the Company relating to the
                  protection of trade secrets, and shall not disclose or use any
                  confidential information with respect to the Company without
                  authorization, except as required in the performance of their
                  duties.

            F.    Acquisitions and Loans of the Company. The Senior Management
                  or their spouses or children shall not acquire any assets of
                  the Company or receive loans or guarantees for loans from the
                  Company in breach of the Articles of Association of the
                  Company.

      (iii) COMPLIANCE WITH THE COMPANY'S POLICY ON DISCLOSURE CONTROLS AND
            PROCEDURES. The Senior Management participating directly or
            indirectly in the Company's disclosure process shall comply with the
            Company's Policy on Disclosure Controls and Procedures and internal
            control rules to promote full, accurate, and timely disclosure in
            the collection, communication and analysis of information relating
            to the filing with the Stock Exchange of Hong Kong Limited, the
            United States Securities and Exchange Commission or other regulatory
            bodies and press releases.

      (iv)  COMPLIANCE WITH LAWS, REGULATIONS AND RULES. The Senior Management
            shall comply with all laws, regulations and regulatory requirements
            in each jurisdiction in which the Company conducts business.

      (v)   FAIR DEALING AND INTEGRITY. The Senior Management should deal fairly
            with the Company's employees, customers and suppliers. The Senior
            Management should

                                       2
<PAGE>

             not take unfair advantage of any of such employees, customers and
             suppliers through manipulation, concealment or abuse of privileged
             information, or misrepresentation of material facts. No actions
             shall be taken by the Senior Management that could undermine the
             Company's reputation of such fair dealing and integrity in the
             course of their performance of duties or in external communication.

      (vi)   ACCOUNTING CONTROLS. The Senior Management shall ensure that all
             transactions of the Company will be properly approved and
             implemented and accurately reflected on the books and records of
             the Company. Falsification of, malpractice or other misconduct with
             respect to, transactions, records, off-balance sheet arrangements
             or other business transactions is strictly prohibited.

      (vii)  PROTECTION AND EFFICIENT USE OF THE COMPANY'S ASSETS. The Senior
             Management shall ensure that all of the Company's assets should be
             used for legitimate business purposes, and shall protect the
             Company's assets and ensure their efficient use.

      (viii) REPORTING OF ANY BEHAVIOR IN BREACH OF THIS CODE. The Senior
             Management shall consult the appropriate personnel of the
             management and the Disclosure Committee at any time if they have
             doubt regarding compliance of their behavior with the Code. The
             Senior Management are required to report to the management and the
             Disclosure Committee of any violations of PRC laws, regulatory
             rules of the places where the Company is listed, internal rules of
             the Company and this Code caused by their own or others' conduct.
             The Company shall make every effort to ensure the confidentiality
             of those furnishing such reports and shall not take any retaliation
             in any form against any person for such reports.

3.    The Senior Management shall comply with the basic principle as required in
      this Code. Any violation of this Code will lead to disciplinary action, up
      to and including termination of employment pursuant to the Articles of
      Association and the relevant regulations, in addition to the punishment
      under the laws of the PRC and the regulatory rules of the places where the
      Company is listed.

4.    A waiver of this Code by the Senior Management can be granted by the Board
      of Directors and must be disclosed to shareholders of the Company;
      provided, however that if the laws of the PRC, regulatory rules of the
      places where the Company is listed and the Articles of Association of the
      Company require that such waiver shall be subject to the approval of the
      general meeting of the shareholders, such requirement shall be followed.

5.    The Board of Directors of the Company shall have the right to supervise
      the compliance of this Code by the Senior Management of the Company, and
      authorize the President of the Company to be responsible for the
      implementation of this Code and observe the compliance hereof. The
      Company's management shall evaluate the adequacy and effectiveness of this
      Code periodically and amend this Code according to the evaluation result
      or as required by the Board of Directors.

6.    This Code shall become effective upon approval by the Board of Directors.

                                       3