The radiated sound from the impacted body must have the information with respect to the impact force and the other properties. We have proposed the method in order to identify the impact force and many properties by analyzing the radiated sound from the impacted body. In the present method, the relationship between the impact force and the radiated sound pressure is calculated by using FEM analysis. And, the time dependence of the impact force, the impact placement, the Young's modulus of the impacted body and the radius of the impact bar are identified by using least square method and the measured sound pressure of the many microphones. By the actual experiments, the efficiency of the proposed method is confirmed.