Abstract: Identity is a important concept that has been extensively recognized in western psychology. Now it has been applied to developmental psychology, social psychology, personality psychology, educational psychology, counseling psychology, and cultural psychology. Unfortunately, the concept of identity lacks a firm definition because of its richness and complexity as well as variously theoretical frames. Accordingly, its theoretical functions are lowered. So this article attempts to grasp the essence of the understanding of identity by different levels and dimensions in western psychology from the analyses of the foundation, positivism research and new tendency about identity. In the end, I put forward some aspects that we must pay attention to as we try to incorporate the concept of identity, and its essence of identity that I draw from above analyses.

Key words: western psychology, identity, concept, analysis