Different needs expressed by people through social relations. Interests essentially belong to the category of social relations. Because people's needs are various, they have various interests. Based on its position in the system of production relations, the possession of material products is material interests, also known as economic interests. In addition, there are political interests and spiritual life interests. Generally speaking, interests mainly refer to material interests. Interest can also be distinguished from different angles. For example, from the perspective of individuals, classes, groups and society, interests can be divided into class interests, national interests, national interests and personal interests; From the whole and local point of view, it can be divided into overall interests and local interests; In terms of time, it can be divided into long-term interests and immediate interests.

Idealists don't admit that material interests dominate people's activities. They usually use empty moral and political preaching to erase or cover up objective material interests. Monk's why the king wants to make a profit and benevolence. "Dong Zhongshu's" taking sincerity as a friend without seeking benefits, knowing its way without considering its merits "is a typical example of this kind of deceptive propaganda. There are also some thinkers in history who have realized the important role of interests in historical activities to varying degrees. Xunzi advocated "beginning of life, its profit is cut off from gold" in China War era. Machiavelli in the Italian Renaissance acknowledged the role of "material interests" in historical development. The Frenchman C.A. helvetius believes that interests can give people happiness and eliminate all human suffering; P-H.D. Holbach defined interest as "the only motive force of human action". However, limited by class and history, these thinkers do not understand the essence of interests, and think that interests are divorced from social relations and stem from human nature or some kind of consciousness and psychological expression. Therefore, they failed to scientifically reveal the relationship between people's ideological motives and material interests in historical activities.