The fracture of the diaphragm is the main failure pattern of the non-contact electronic horn. The spring steel strip 50CrVA which is cold rolled was applied to manufacture the diaphragm of the non-contact electronic horn by means of sheet metal forming. The combination of the experiments with finite element method (FEM) was used to reveal mechanism of fracture failure of the diaphragm. The displacement field, the effective strain field and the effective stress field at the maximum amplitude value are obtained by simulating the genuine vibrating state of the diaphragm with the help of ANSYS finite element code. The maximum stress zone of the stress field of the diaphragm is responsible for the fracture zone of the diaphragm. The fatigue test of the diaphragm and microscopy of the fractured diaphragm indicates that the fracture pattern of the diaphragm agree well with finite element simulation results. Eventually, the measures to prevent the fracture of the diaphragm were taken in order to increase the endurance of the diaphragm.