With continuous changes to energy-saving requirements, the task of train aerodynamic optimization becomes important. Traditional aerodynamic optimization of a high-speed train is carried out assuming the same shape of the head and tail cars, which ignores the combined effect of the two cars on aerodynamic forces. The streamlined structure of the train has different effects on the aerodynamics of the head and tail cars. In-depth study of these effects will help engineers improve their shape design capabilities. Based on the surrogate model method, this paper studies the influence of five shape parameters of the streamlined area on the resistance of the head and tail cars and the lift force of the tail car of CRH380A, and compares the aerodynamic performance of the two optimization schemes. The research results show that the optimization direction for reducing drag of the head car is opposite to that for reducing the drag and lift of the tail car, while the optimization directions for reducing both drag and lift for the tail car alone, are roughly the same. Therefore, the same shaped head and tail cars are problematic for improving aerodynamic performance. After optimization, the head car \' s resistance, the tail car \' s resistance, and the tail car \' s lift of the train with the same shape of head and tail cars are reduced by 1.7％, 0.5％, and 3.5％, respectively. The train with different shapes had values decreased by 5.6％, 1.4％, and 7.5％, respectively. The optimization effect of the latter is more than twice that of the former.