Several surrogate models such as response surface model and radial basis function and Kriging models are developed to speed the optimization design of vehicle body and improve the vehicle crashworthiness. The error analysis is used to investigate the accuracy of different surrogate models. Furthermore, the Kriging model is used to fit the model of B-pillar acceleration and foot well intrusion. The response surface model is used to fit the model of the entire vehicle mass. These models are further used to calculate the acceleration response in B-pillar, foot well intrusion and vehicle mass instead of the finite element model in the optimization design of vehicle crashworthiness. A multi-objective optimization problem is formulated in order to improve vehicle safety performance and keep its light weight. The particle swarm method is used to solve the proposed multi-objective optimization problem. The simulation results show that the B-pillar acceleration and the foot well intrusion are reduced 4.9%, 6.31% respectively. The entire vehicle mass is reduced 4.9kg. The proposed combined surrogate models and their applications in the optimization design of vehicle crashworthiness provide an important design method and demonstrates potential application in vehicle body design.