East Asia draws the attention of experts in recent years due to the unprecedented economic and political growth of the countries of the region. However, despite the significant role that the region plays in world politics and economics, the absence of security mechanisms and the presence of several potential spots of conflicts, such as the contradiction between China and Japan, make the region volatile. The article makes an attempt to understand the root of the Sino-Japanese relations and their conflicting potential using the classical concept of “security dilemma”. The research is based on the theory of realism and the idea of “security dilemma” in the understanding of this school of international relations. The article argues that the current problems in Sino- Japanese relations, including territorial disputes and the problems of the interpretation of historical events, have deeper roots that can be explained using the concept of “security dilemma” and the historical competition for regional leadership in East Asia. The article also pays attention to the importance of preserving stability in the region for modern Chinese foreign policy to secure the reinforcement of the political influence of China on a more vast, global level. Thus Sino-Japanese contradiction and the “security dilemma” in the region play an important role in Chinese foreign policy as a whole.