The category of interest plays an important position in the theoretical system of the historical materialism. In their classic works, Marx and Engels express a series of interest viewpoints. For instance，they believe the material benefit is the inherent power of all human social activities. Also they think that interest in essence is a kind of social relation category. In the society of interest differentiation and diversified interest subject，people should abide by Marx and Engels' interest ideas and continue to deepen their interest theory in the new historical era in order to reconstruct interest system which adapts to the development of socialist market economy and promote the harmonious development of society.