This paper presents the scaled similitude rule for train collision, which follows the principle of acceleration consistency. If the similarity ratios of mass and initial impact speed of cars, crushing force, and initial length of the energy absorbing structures of trains with different proportions meet the requirements of the scaled similitude rule, the impact accelerations of each are considered to be consistent. The accuracy of the scaled similitude rule was analyzed by MATLAB simulation, which is based on the multibody dynamics theory. Before the analysis, the validation of the MATLAB model was verified based on the experimental model. Then the train-to-train collisions for two eight-car train sets with different similarity ratios were tested. Finally, the scaled similitude rule presented in this paper was found to be effective when the impact characteristics of the two models were compared.