2012 is the 40th anniversary of the normalization of Sino-Japanese diplomatic relations. Reviewing the economic relationship between Japan and China over four decades, although there are many difficulties, but the overall tone is development and expansion. The development of economic relations has both the necessary conditions and sufficient conditions, but in different periods it has shown different characteristics, which could be seen from the Sino-Japanese trade and direct investment and other areas. Economic relations of 40 years, has gone through from "stable" to "harmonious, competition", and currently been battered by the deterioration of relations between Japan and China as a result of the territorial dispute. Both sides should stand on a higher level of "understanding, cooperation and trust" to seriously handle this situation. <<