He joined China Offshore Oil Corporation on 1982. 1985 to 1996 as manager of Bohai Oil Commercial Company and Bohai Oil Transportation Company under China Offshore Oil Corporation.
From 1996 to 2003, Mr. Cao successively served as deputy general manager and general manager of China Offshore Oil Bohai Company.
From April 2003 to July 2004, Mr. Cao served as assistant to the general manager of China Offshore Oil Corporation.
From August to 20, 200410, Mr. Cao was appointed as the deputy general manager of China Offshore Oil Corporation. Mr. Cao is also the chairman of CNOOC Base Group Co., Ltd., a subsidiary of China Offshore Oil Corporation.
On April 20 12, he served as the external director of China Shipping (Group) Corporation.