Abstract: The disclosure provides a construction method including steps of: constructing a detailed model and a simplified model of the rail vehicle using finite element method based on the three-dimensional structure of the rail vehicle; initially setting the simplified model in accordance with the detailed model, including specifying materials, mechanical properties parameters, and mass point; setting different simplification thickness ratio to obtain a plurality of sets of the simplified models, designing longitudinal and lateral collision conditions, and in each type of the collision conditions, performing collision simulations on the detailed model and each set of the simplified models under each thickness ratio to obtain respective collision response curves; calculating a total CORA value corresponding to the plurality of sets of the simplified models; selecting an optimal simplified model from n sets of the simplified models with the highest total CORA values.