Abstract: To improve the efficiency and accuracy of vehicle body lightweighting, the sub-model technology and response surface surrogate model is integrated. Taking the body of an A-type aluminum alloy metro car as the research object, the static strength analysis of the finite element model of the whole vehicle was carried out according to the EN-12663 standard to determine the part with the maximum stress. The displacement interpolation technique was used to construct the sub-model of the car body, and its accuracy was checked. The APDL language was used to establish the parameterized sub-model, and the response surface surrogate model of the thickness parameters and quality of the car body was established by combining the central composite design, and the MOGA algorithm was used to solve the surrogate model. The results show that the optimized body structure not only meets the strength requirements, but also reduces the weight by 21 kg.