This study investigates the mechanism of wheelset longitudinal vibration and its influence on wheel periodical wear. A longitudinal wheel/rail friction model was created after analyzing the characteristics of wheel/rail longitudinal friction that fit our study. This friction model is then incorporated into a vibration analysis of a wheelset coupled with a single-wheelset longitudinal dynamical model. The response of the single-wheelset system both considers the effects of track excitation and small randomly varying velocity, and the wheelset longitudinal random vibration process is held constant. Meanwhile, from the micro perspective, wheelset longitudinal vibration will cause changes of wheel/rail contact parameters mainly in the natural frequency which will cause periodical wear. Such wear is due to the natural frequency of wheelset longitudinal vibration being the same or doubled.