EXHIBIT 12.1


                                 Certification

I, Chengyu Fu, Chairman and Chief Executive Officer of CNOOC Limited, certify
that:

1.   I have reviewed this annual report on Form 20-F of CNOOC Limited;

2.   Based on my knowledge, this annual report does not contain any untrue
     statement of a material fact or omit to state a material fact necessary
     to make the statements made, in light of the circumstances under which
     such statements were made, not misleading with respect to the period
     covered by this annual report;

3.   Based on my knowledge, the financial statements, and other financial
     information included in this annual report, fairly present in all
     material respects the financial condition, results of operations and cash
     flows of the registrant as of, and for, the periods presented in this
     annual report;

4.   The registrant's other certifying officers and I are responsible for
     establishing and maintaining disclosure controls and procedures (as
     defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant
     and have:

     (a)  designed such disclosure controls and procedures, or caused such
          disclosure controls and procedures to be designed under our
          supervision, to ensure that material information relating to the
          registrant, including its consolidated subsidiaries, is made known
          to us by others within those entities, particularly during the
          period in which this annual report is being prepared;

     (b)  evaluated the effectiveness of the registrant's disclosure controls
          and procedures and presented in this annual report our conclusions
          about the effectiveness of the disclosure controls and procedures,
          as of the end of the period covered by this annual report based on
          such evaluation; and

     (c)  disclosed in this annual report any change in the registrant's
          internal control over financial reporting that occurred during the
          period covered by this annual report that has materially affected,
          or is reasonably likely to materially affect, the registrant's
          internal control over financial reporting; and

5.   The registrant's other certifying officers and I have disclosed, based on
     our most recent evaluation of internal control over financial reporting,
     to the registrant's auditors and the audit committee of registrant's
     board of directors (or persons performing the equivalent functions):

     (a)  all significant deficiencies and material weaknesses in the design
          or operation of internal control over financial reporting which are
          reasonably likely to adversely affect the registrant's ability to
          record, process, summarize and report financial information; and

     (b)  any fraud, whether or not material, that involves management or
          other employees who have a significant role in the registrant's
          internal control over financial reporting.



Date:  June 22, 2005



                               By:    /s/ Chengyu Fu
                                    -------------------------------
                                    Name:   Chengyu Fu
                                    Title:  Chairman & Chief Executive Officer