In this paper, aimed at wheel-axle with axle load of 30 ton, the three dimensional finite element model was established, and the interference fit between wheel and axle was considered. According to Standard EN13103, the vertical load and the lateral load were determined, and then the stress distribution of axle was computed under two cases: only vertical load and both vertical and lateral load. The result shows that: the increase of axle load causes the increase of slip between axle and hub, which leads to an increase of fretting damage and a reduction in fatigue life. In addition, Dang Van criterion was employed to evaluate the fatigue of the whole axle. It is found that the transition zone next to wheel seat and the interface of hub and axle are dangerous points, which is in accordance with the practice.