PetroChina Co. Ltd is mainly engaged in the generation and sale of petroleum and natural gas including the exploration, development and production of crude oil and natural gas, refining, transportation, storage and marketing. The company also imports and exports crude oil and petroleum products including the production and sale of chemical products and the transmission and the marketing and sale of natural gases. It has several petroleum and gas districts in areas such as Daqing, Liaohe, Xinjiang, Changqing, Dalimu and Sichuan provinces and three 10 million-ton grade refineries as well as a network supply chain that covers all of China.

In 2000, the American depositary shares of PetroChina were listed on the NYSE and the company's H-shares were listed in Hong Kong.