The embodiments of the present invention provide a track dynamic stiffness test method and system. The method comprises the following steps that: an excitation force in a preset excitation frequency range is applied to a track within preset time; force signals and displacement signals on the track are collected according to a preset sampling frequency, so that corresponding force signal sampling points and displacement signal sampling points can be obtained; data processing is performed on force signal sampling points in a preset time interval, so that corresponding change relationships between the force signals on the track and excitation frequencies can be obtained; data processing is performed on displacement signal sampling points in the preset time interval, so that corresponding change relationships between the displacement signals on the track and the excitation frequencies can be obtained; and corresponding change relationships between the dynamic stiffness of the track and the excitation frequencies can be obtained according to the corresponding change relationships between the force signals on the track and the excitation frequencies, and the corresponding change relationships between the displacement signals on the track and the excitation frequencies. The measurement accuracy of the track dynamic stiffness test method and system is high. With the track dynamic stiffness test method and system adopted, the dynamic stiffness values of the track at different vibration frequencies can be measured comprehensively.