With the development of FDI and international trade of China, it seems to be particularly important for China to analyze the relation between FDI and international trade. Foreign Direct Investment is becoming main strength for influence of trade between developing countries. As result, the interaction and between international trade and FDI are strengthened day by day. The paper will research the relation between Korea’s investment and Sino-Koeran trade.Since the normalization of the relationship in 1992, trade and Korea's investment to China has increased rapidly. As a result, China is now Korea's largest trade partner and the largest investment destination. It is beneficial for making Chinese economic policy concerning Korea to study the relation between Korea's direct investment in China and Sino-Korea's trade. At present, in China there are few systematic researches on the relation between FDI and international trade. With the Gravity model and Granger Causality Test, the author analyses the relation between Korea's direct investment in China and Sino-Korean trade. This paper introduce the theory about the relation between the two country, And introduce the key problem between the research of trade and investment, mainly including the proposition of the question, The second part is the analysis of current situation about China's reform and opening up and how to develop oriented economic. FDI and trade are very important to China's development. The part summarizes overall development situation of FDI and foreign trade of China. It has analyzed the rapid development of foreign trade since the reform and opening in three respects: the rapid growth of foreign trade, imported and exported goods structure's improvement and market pluralism of foreign trade. This paper by the angle of Korea's investment to China and the China's export to Korea, China's import from Korea, and the trade and investment between the two country, the paper used quarterly data from 1994-2013 of the two county's investment and the trade authenticated the relation between them. The result shows that there is a long-term complementary relation between the two. On the last part, Based on the above achievements, the conclusion of the paper and proposes relevant policies about promoting Korea's direct investment and Sino-Korean trade. The Foreign Direct Investments has driven the growth of the total amount of Korea and China's trade, and will also have a positive impact on optimization of China's export structure.Keywords: Korea's Direct Investment in China, FDI, Gravity Model