The underframe is the key bearing part of the body of EMU,and the rigidity and strength of its structure design have a great influence on the safe operation and performance of EMU. The strength of the underframe structure of the 250 km/h EMU is analyzed and studied by FEM ANSYS based on the analysis of whole car body. Under typical load,the local stress of stress concentrated parts of underframe（traction beam,etc.） is analyzed and optimized,and the static strength test is carried out on the end car body structure of 250 km/h EUM. Under various operating conditions and loads,the stress and synthetic stress of each stress measuring point and displacement of displacement measuring point are all less than the elastic limit of the material used,and the structure design of the underframe is reasonable.