| In order to consider the characteristics of high-speed train, slab ballastless track and bridge interaction, the train is simulated as a mass-spring-damped multi-rigid body constrained system, and the motion equation of the car-rail-bridge coupling system is established. In this paper, firstly the coupling motion equation of the system is established, then the influence of parameters such as train driving state (speed, acceleration), train suspension coefficients, vehicle-track-bridge connection coefficients on the dynamic performance of trains, tracks and bridges is analyzed when the two-line train passes through the high-speed railway bridge under different working conditions. The results show: (1) The change of acceleration and speed of the train has different degrees of influence on the coupled system. With the increase of train speed and acceleration within a certain range, the displacement vibration response of the car body own structure is gradually reduced, but the displacement vibration response of the rail and bridge structure is gradually increased. (2) The change of train suspension parameters has a great influence on the train own structure, but has little effect on the rail and bridge structure. (3) The increase of the primary stiffness coefficient of the car body will cause the vibration response of the train system structure to increase, but the increase of the secondary stiffness coefficient of the car body suppresses the vibration response of the car body structure. (4) The vibration response of trains, rails and bridges is not easily affected by the connection parameters between the rails and the bridges, except that the maximum acceleration of the rails decreases almost linearly with the increase of the continuous stiffness coefficient.