ABSTRACT One of the most important issues in Knowledge Management is ¡§knowledge transfer¡¨ and ¡§knowledge share¡¨. The knowledge transfer in organization needs some carriers and medias, and that is one of the factors to influence knowledge management performance. Base on the issue, this reaserch wil study the importance of media richness perception and it¡¦s influence factor from system effective perspective. This study develops based on the channel expansion theory (Carlson and Zmud,1994) and social influence (Fulk et al., 1990) . Four experiences of constructs in channel expansion theory were theexperience with the channel, experience with the messaging topic, experience with the organizational context, and experience with communication coparicipants. And, we will survey the e-learning environment in the NSYSU as our study sample. An empirical survey methodology is applied to test the research model and hypotheses proposed in this study. Five out of seven hypotheses are validated in our research model with Path Analysis. The research result reveals that the social influence dimension has the most impact on the perception of channel; on the other hand, experience with the channel and communication partner also result validates. Keywords: knowledge management, channel expansion theory, information systems effectiveness