In order to analyze the effect of geometric parameters on the structural integrity of star grain, the parameterized model of star grain was constructed through PCL(Patran Command Language) on the platform of FM software MSC.Patran/Nastran. The law of maximum Von Mises strain variation with geometric parameters was studied, and the geometric parameters sensitivity was analyzed based on the parameterized model. The results show that grain web thickness, star angle coefficient, star-hole number, and the rounding radius of groove top have great effect on the structure integrity of star grain. Therefore, more attention should be paid to these parameters in motor design. The analytical method and conclusion are beneficial for designing SRM.