The damage process of polymer material under high cycle fatigue was analyzed based on the theory of damage mechanics, the fatigue process was calculated by means of Visual Basic, and simply drawing tests were carried out to obtain the parameters of the material, which were subsequently used in the numerical simulation of polyethylene damage mechanics. The damage condition and lifetime under the high cycle fatigue were analyzed by damage mechanics, with which the damage before the craze formation could be simulated, and the lifetime of the material could thus be predicted, saving great many time and funds