Abstract: Friction stir welding（FSW） is a new solid state bonding technology, which can be used for fusion welding of wieldable non-ferrous metals.This paper summarizes and analyzes the structure of friction stir welding machine and the working principle of friction stir welding, determine the overall structure design scheme suitable for electric vehicle battery package friction stir welding machine; Based on the calculation of the basic parameters, the design and calculation of the mixing head, table and spindle system of the friction stir welding machine are completed.The 3 D model of the main parts of the friction stir welding machine for electric vehicle battery pack is established by using Solid Works 3 D software, and the motion simulation is carried out.The quality of friction stir welding is improved and the application of friction stir welding technology is more extensive.