Abstract: Analysis of stick-slip vibration of two contact bodies is executed in detail based on the dynamics of stick-slip systems and principle of non-linear friction. A stick- slip vibration equation is established for SDOF system, and conditions which stick-slip vibrations begin to occur are deduced, the effects of drive velocity exerted on the range of slip are analyzed, and the results of numerical calculation show that there exists a linear relation between them . Based on the creep force, the possible torsion stick-slip vibration of constrained wheelset is also analyzed, pointing out the reasons of producing stick-slip vibration of wheelset in the inner side when curving and uneven frictions on the contact surfaces of the rails and wheelset.