Aim To realize optimized construction and volume of rail wheel and axle in complex loads with finite element analysis. Methods 3D model is build by means of Solidworks software. The complex environment in running rail including the machanical load and the thermal stress resulted in braking process is simplified. Contact unit models are used in the contacting parts. This work performs the stress analysis of a wheel and axle with ANSYS program. Results The stress distribution is solved in different boundary conditions. Optimized design of Rail wheel and axle is finished. Conclusion This result satisfies our national railway standard. The maximum stress is less than the yield stress.