Price dispersion is an indication about the efficiency of market. An evolution model of price dispersion (EMPD) is put forward in order to research the efficiency of C2C e-business market. By concluding the influence factors of price dispersion and analyzing the trade behavior in C2C e-business market, four representative factors that are business number, business credit, customer type and transfer cost are chosen as research object. On the basis of these four influence factors, EMPD is established by using multi-agent method and repast simulation platform is utilized to simulate the model. Three functions are established in EMPD from the view of business which is relate to expected sales, pricing and sending probability of inferior while two functions from the view of customer which is related to transfer cost and purchase. At last, the method and thought of simulation are discussed for the preparation of the next simulations.