Abstract: Erikson is the first person who advanced the problem of ego-identity. And he also described it from many perspectives. But he didn’t do empirical research into it. However, Marcia found 2 dimensions from the complex ego identity so that people can do empirical research into ego identity. Later, many studies attributed the development of identity to personal factors, which made it difficult to explain regression. So people found that contextual factors were also factors which affect the development of ego identity. Now many researchers acknowledge that personal and contextual factors both affect the development of ego identity. And some of them have put forward some theoretical models. At the same time, other researchers hope to explore the relationship between ego identity and other constructs. And in the future, the construct validity of ego identity and its development mechanism, and the relationship between ego identity and other constructs will still be hot topics

Key words: ego identity, exploration, commitment, regression