Virtual Team means ”A cooperative unit which allow members interact on the network to accomplish its mutual goal, beyond the space and time”. Due to lacking of face to face communication as performed by physical team. How the impact of virtual team member's interaction pattern and cooperative behavior on the team's performance is quiet interested to MIS researchers. The purpose of this study is to investigate the influence of member's role playing on virtual team's performance among different group development stages. The role playing and group development process of 24 virtual teams in a cyber university were examined. Contents analysis is used to collect and analyzed the member's interaction data which were posted on the team's BBS system. Finally, the research results suggest the patterns and intensity of role playing (such as initiator, gatekeeper, encourager, opinion seeker, orienter, etc.) between high performance teams and low performance teams are quite different.