Abstract：For the problem of high speed train suspension parameters matching, using the method of system engineering, taking the bogie system, the car body, and the seat system as a unified whole system, a vertical dynamic model of high-speed train bogie-body-seat coupling system is established and the interaction between the systems is discussed. Based on this, taking optimal ride comfort as target, the optimization of the vertical suspension system of high-speed train under the excitation of track random irregularity is carried out and a joint optimization method of vertical suspension parameters for bogie-body-seat coupling system is built. Through numerical computations, it is known that the ride comfort of high-speed train has been significantly improved after the vertical suspension parameters been optimized, and the body vertical weighed root mean square acceleration value at different positions is reduced by more than 18.52%, the results show that the joint optimization method of vertical suspension parameters for bogie-body-seat coupling system established is workable. This research provides an efficient method for the selection of vertical suspension parameters of high-speed train.