Finite element model of a BIW was built by applying HyperMesh software and based on lightweight requirements, this paper proposed to replace advanced high-strength steel with hot stamping steel PHS1500 for BIW A-pillar reinforcement plates and replace B410LA with DP780 for the front longitudinal beam, and replace QSTE500TM with QP980 for the front guard cross member, the paper also proposed to reduce thickness. According to C-NCAP management rules, LS-DYNA was applied to perform a 100% overlap rigid wall collision analysis for the BIW model at 50 km/h. The results show that based on the results of the frontal collision analysis of traditional high-strength steel materials, after the material upgrade the intrusive amount at A-pillar reinforcement site and fireproof board leg inspection point decreases by 8.9% and 15.9%, respectively, the frontal collision performance of the BIW has been greatly improved, and the weight is reduced by 6.224 kg.