In this paper, a certain type of ammunition Water Cooler Thermostat bracket was studied, the stress distribution under working load is calculated by static analysis and display dynamic analysis, the stress distribution result show that the maximum load during the working cycle is the instantaneous impact force.Through ANSYS software, Goodman theory method was used to modify the stress, the fatigue life of the bracket and the safety factor of each position Vegetable / Fruit Cutters of the bracket are calculated.It can provide for life prediction and reliability research of the projectile support.