Abstract: Multiple principal-agent relations exist in the war material contract reserve. Based on the Game Theory, this study analyzed profit and loss of the military, military representative and contract reserve enterprise, and investigated the factors of punishment for collusion and loss of reputation. Based on the forming condition of collusion, it built the model of collusion-prevention for the war material contract reserve, worked out the mixed strategy equilibrium, and analyzed it. The mixed strategy equilibrium reflects the best probability for contract reserve enterprise and military representative to collude, and the equilibrium probability for the military to choose supervision. It calculated the reasonable combination of supervision strength and cost, maximum interests of supervision. Through simulation, model parameters are carried out to estimate the degree of parameter sensitivity, the key variables to identify collusions, providing references to improve the supervision procedure of the war material contract reserve.