On the basis of available literature, a model of the relationship among temporary group buildup, swift trust, knowledge sharing and temporary group performance is proposed. According to the empirical method, it studies the regulating effects of knowledge sharing on the relationship between swift trust and performance of temporary group. We design questionnaires including the temporary group building factor form, the swift trust form, knowledge sharing form and the performance form, and analyze data using SPSS11.5. It is concluded that the influencing factors of temporary group is correlated with knowledge sharing and swift trust positively, and temporary group knowledge sharing is correlated with swift trust and performance positively. Possessing regulating effect, knowledge sharing can obviously boost up swift trust and performance of temporary group.