“Overseas Chinese” are neither a major actor nor a non-major actor in international relations. It is only an ethnic group between China and country of immigration. Depending on the country，the problems it creates are unique. The existing studies of Overseas Chinese in Japan either regard the Overseas Chinese as an independent variable that it affects China-Japan relations or the dependent variable that it is reflected. However，according to the results of the analyses in this paper，the living status of Overseas Chinese in Japan has been deeply influenced by relations between China and Japan including historical conflicts and survival interests. The function proposed by scholars that Overseas Chinese are able to enhance the country’s soft power and public diplomacy，in fact，is difficult to play out because of the restrictions of China-Japan relations. In recent years，due to the territorial issue of “purchase” of the Diaoyu Islands and other events，more and more Overseas Chinese have decided to come back from Japan and settle down in China. The Chinese population in Japan will continue to decline unless the China-Japan relations had been improved.