The frame of battery box used in high-speed train is mainly composed of square tube steel profile and welded structure of bending steel plate. Aiming at the further lightening requirement of 400 km/h high-speed train,this paper designs a battery box with aluminum alloy profiles and bending plates as the main structural parts,realizes the lightening of the whole box structure,which is beneficial to train speed-up and energy consumption reduction. Based on Solidworks,three-dimensional model of the battery box is built,and Ansys Workbench is used to analyze its structural strength under ultimate load. At the same time,the natural frequency and mode shapes of battery box in the free state are studied. Through modal analysis and static strength analysis,the safety and reliability of this new structure are verified.