According to the three-dimensional theory of sociologist Schutz, there are three basic needs in the action of interpersonal social interaction, namely, the need of inclusion, the need of domination and the need of emotion. Through the three-dimensional theory, he put forward a group positive sum principle, that is, the process of group formation is tolerance control emotion, the process is emotional discord difficult to contain finally out of control group dissolution. The principle of group decomposition is contrary to the formation process.