Abstract: The petroleum industry is usually divided into three major components: Upstream, midstream and downstream. Oil companies, not only International Oil Companies(IOCs) with long history but also new emerging National Oil Companies(NOCs), playing an important role in the world petroleum industry, have been implementing a common strategy of the integration of upstream and downstream business. But, it was not easy for oil companies to form their integrated business structure or the industrial chain, and most of them had to make necessary adjustment for adapting the environment changes. Chinese oil companies may learn a lot from the experience of the world major oil companies' integrated development strategy.