Carbon Fiber Reinforced Plastic (CFRP) were used to replace traditional metals to construct battery pack box to achieve lightweight design of battery pack box. Firstly, based on performance requirements, finite element analysis was conducted for the dynamic and static performance of carbon fiber battery pack, topography and size optimization was carried out on the upper cover plate, and structural optimization was made on the lower box body respectively, which increased the first-order natural frequency to 50.63 Hz and reduced weight of the lower box by 31.1%. Secondly, optimization analysis was made on the box layer, and based on the Isight platform, multi-objective optimization was conducted on the weight and first-order natural frequency of the lower box, meanwhile the entropy TOPSIS decision-making method was used to determine the optimal layer design scheme. Finally, the layer sequence was optimized by considering the lamination board laying process. The optimization analysis results show that lower box achieves a weight reduction of 58.9%, and both the maximum displacement and maximum stress under all operating conditions were reduced, and the dynamic and static performance of the battery pack box has been improved.