Abstract: The fatigue failure of metro vehicle wheel results from the high-frequency wheel-rail loads and thermal loads duo to frequent braking during service. The analysis method for mechanical stress and thermal stress of metro vehicle wheel under full service cycle is put forward on the basis of axial symmetry finite element model. And then the superimposition principle of mechanical loads and thermal loads is investigated. Thus, the method to assess the fatigue strength of the metro vehicle wheel is established. Finally, a case study shows the influence of braking and tread wear on the wheel fatigue strength.