With the pervasiveness of online community, people expand their identities by acquiring memberships of different online communities. Online community not only provides contexts and tools for people to build up and manage new identities, but also evokes people to have emotional experience. This research aims to understand how member's emotional experience induced by different community artifacts (contents or other members) will influence the participation behaviors through the understanding of their relationships with the online community. This research proposes that emotional experience changes how one identifies with the community, hence influences the behaviors that relate to the self-definitions, e.g. self-disclosure, knowledge contribution, self-presentation and social interaction. Taken the perspective of broaden-and-build theory and social identity theory, this research proposes that positive emotional experience promotes open-minded coping, and consequently expands the self-concepts and become more social inclusive.