Based on the theoretical analysis of the substitution effect and complementary effect of cross border electronic commerce on the international of ethnic Chinese networks, this paper makes an analysis on the results of market equilibrium and trade effect by using the Cournot model and an empirical test on the above mentioned impact by using the panel data. The research indicates that the complementary effect is more obvious than the substitution effect. On the one hand, the impact of Chinese business network on export trade is particularly significant, while cross border e commerce platform is mainly based on export trade, so cross border e commerce has great influence on the export trade of ethnic Chinese network. On the other hand, cross border e commerce platform is biased towards differentiated product trade, thus cross border e commerce has a great impact on the differentiated product trade of Chinese business network. That is to say, the complementary effect is manifested in export trade and differentiated product trade.