Wheel set longitudinal vibration is a self-excited vibration when railway vehicle is running on the track, which is one of the important reasons of wheel tread spalling problem, and will cause the dynamic performance worse of the vehicle. To investigate the happen mechanism of the wheel set longitudinal vibration, the 7 degree of freedoms wheel set longitudinal vibration model which considers the torsion vibration of the wheel axle was set up based on Matlab. From the point of view of frequency and vibration, put forward one kind of forecast method of the happen of wheel set longitudinal vibration. Wheel set longitudinal vibration will lead car body to suffer an impact in the longitudinal direction and this would cause car body tremble and have a big vertical vibration. Take the locomotive which has severe wheel tread spalling problem running on the Kunming meter track for example to test the effect of the wheel set longitudinal vibration theory to solve the wheel tread spalling problem. Solve wheel tread damage from the aspect of dynamic is an evolution method and Wheel set longitudinal dynamic is the extension of the wheel/rail dynamic.