The ambient temperature is objective existence of natural phenomena in the process of wheel/rail sliding. The surface temperature of wheel/rail and the number of heat between the wheel/rail and air could be determined by the size of the ambient temperature. Ambient temperature is taken to be 20℃ in the analysis of the wheel/rail sliding contact by most researchers. The analysis of three dimensional thermal elasticplastic of wheel/rail sliding state is implemented by using the finite element software of ABAQUS. The change of temperature field and the changing characteristics of wheel/rail contact area are analyzed in different ambient temperature under specified sliding speed. The results show that the increase of ambient temperature will not cause the huge change of temperature field of wheel/rail contact region, and the effect of numerical change of ambient temperature on wheel/rail sliding friction contact is relatively small. The present study proved that ambient temperature of heat is relatively small as compared to the wheel/rail friction heat and it has little influence on the results of numerical simulation. Therefore, the ambient temperature can be taken as a constant value in the numerical simulation of wheel/rail.