Since China became a net oil importer in 1993, China¡¦s remarkable economic growth has fueled a demand for oil that has outstripped domestic sources of supply. China¡¦s reliance on oil imports to satisfy its oil requirements has become the potential threat to the national security. Therefore, The Chinese government advocated the ¡§Go Abroad¡¨ strategy and support overseas investment by the Chinese state-owned oil companies to diversify China¡¦s oil supply. This paper focuses on the development of Chinese oil companies¡¦ overseas investment based on the political-economic approaches to oil security. The research problem of this paper is: Why did the Chinese government decide to drive the state-owned companies¡¦ overseas investment? In what condition did the Chinese government interfere in overseas investment activities? What is Chinese oil companies obtained in their ¡§Go Abroad¡¨ activities? What Challenge will Chinese state-owned companies¡¦ investment in overseas oil fields face? The conclusion of this paper is that the incomplete business activities which the government¡¦s intervention in the overseas investment will lead to can¡¦t ensure oil security. It can be predicted that the Chinese state-owned oil companies¡¦ will have the economic nationalism guide the direction of their overseas investment development, but they will increasingly participate in the free trade mechanism in the international oil market.