This is a selection of three key factors that are crucial to china-japan relations and Japan’s policy in China，the Japanese foreign strategy，the fundamental elements of Japanese diplomatic strategy and foreign policy decisions，and their internal contradictions，the defining variables of Japanese foreign policy，and their respective forms and changes，and the correlation between each other. In the strict sense，Japan’s policy toward China（foreign policy）and the analysis of the diplomatic strategy including its inherent paradox，and the resulting changes in the diplomatic relations between China and Japan，are in diplomacy and analyze the argument in the category of foreign relations，and not directly involved in domestic politics in both China and Japan，especially in Japan’s domestic political and social and economic variables and their effects. Therefore，when examining china-japan relations in east Asia，before we accept the concept of confrontation and competition between China and Japan in various fields，it is necessary to carefully comb china-japan relations from the perspective of east Asia and the whole world as well as from the political，economic and cultural fields，and conduct an analysis and research on china-japan relations from all aspects of history and reality.