Abstract: Based on the coupled vibration theory, dynamical models and equations of motion were set up respectively to an X-style arch bridge and vehicles. Vehicles and X-style arch bridge were divided into two vibration subsystems connected by nonlinear contact forces between wheels and tracks, and the iteration method was used to solve the two subsystems. A self-developed software analyzing the coupled vibration of vehicles and bridge was applied to an X-style railway arch bridge. The vertical and transverse displacements of this bridge, its dynamic amplificatory factor, and the derailment and offload factors of vehicles were evaluated. The result shows that under the discussed conditions, they all meet the current national criteria.