Targeting at the ubiquity of more bargaining power that upstream retailer has than downstream supplier in a supply chain, evolutionary mechanism of vender managed inventory model is discussed. Under traditional inventory mode and VMI mode, supply chain models with powerful retailer are constructed respectively so as to obtain a payoff matrix of different inventory strategies. On this basis, by using double groups’ evolutionary method, evolutionary stable strategies (ESS) are derived and analyzed in short and long term perspective. It is revealed that the intrinsic evolutionary mechanism and key factors to the winwin implementation of VMI in this paper. It’s shown that the evolutionary stable strategies in different periods are respectively (not implementing VMI, not implementing VMI) and (not implementing VMI, not implementing VMI) coexisting with (implementing VMI, implementing VMI) as the transaction quantity increases in the long run. In addition, the effects of profit change, investment cost and penalties on equilibrium have also been analyzed.