The global value chain dominated by multinational corporations has become an important form of economic globalization. In global value chain, the relation between upstream enterprises and downstream enterprises is a key for us to understand economic globalization. In this paper a game model analyzing the relation of upstream and downstream enterprises is constructed. From the proportions accounted for by upstream enterprises and downstream enterprises, we have the conclusion that the downstream enterprises are low-locked. There are three obstacles of breaking through the low-locked condition. And we propose suggestions from four angles of cultivating domestic market, developing financial market, changing mental model of enterprises, and reconstructing corporation culture.