Abstract: The dynamic interaction between high-speed train and slab track is studied by theoretical analysis and field test, and an analysis method for spatial vibration of high-speed train and slab track system (hereinafter referred as the system) is proposed, where the motion of each vehicle is assumed to have 26 degrees of freedom (DOFs). According to structural characteristics of the track, the new track segment element is developed to describe its spatial vibration, which has 32 DOFs. The spatial vibration equations of the system are established on the basis of the principle of total potential energy and according to the rule of “set-in-right-position” in formulating system matrixes. The equations are solved by Wilson-θ method. The track displacement, the derail factor, wheel load reduction rate and lateral wheel-rail force are calculated and compared with the experimental results. It is shown that the calculated results agree well with the measured results, demonstrating the correctness and feasibility of the proposed method. The effect of track stiffness on spatial vibration responses of the system is also investigated in the paper.