Abstract: In this paper, a vibration testing method to determine the stiffness of the badminton rod is presented. The badminton rod is simplified as a mass-spring system of a single degree of freedom, the natural frequency of which is measured by the vibration testing method. Then the stiffness parameter of the rod can be calculated by the frequency formula. The suggested vibration testing method is more convenient and accurate than the current flexible test method, and can be used as a standard method of judging the soft and hard degree of a badminton rod.