Knowledge sharing is one of the important branches of knowledge management Two research paradigms are put forward in this paper, which are known as technology-centered and human-centered paradigm Under such framework, this paper reviews the existed research on knowledge sharing from seven perspectives, which are communication, tool, interaction, learning, power, market and social exchange Finally, three directions of knowledge sharing research are put forward Those are revolution from the technology-centered paradigm only, paying more attention to individual level and taking culture into account