In recent years, speed of high speed railways is raised by improvement of technology about vehicle, truck and electric. However, speedup of railway vehicle caused high frequency vibration; therefore riding comfort deteriorated by resonance with the back seat. In this study, the authors aimed to construct the passenger model with multi-body dynamics (MBD) to propose a seat design guideline to reduce vibration including high frequency. First, in order to construct the passenger model, the authors investigated the vibration characteristic of the passenger and the seat by vibration test. Vibration test was performed by inputting linear sweep wave from 0.2Hz to 40Hz in front-back direction or vertical direction to floor, and acceleration of the passenger's head, shoulders, chest, belly, and thighs and the seat were measured. Next, a passenger model with 13 mass and 23 degrees of freedom was constructed by MBD. After that, simulation studies were carried out by inputting linear sweep wave from 0.2Hz to 40Hz in front-back direction or vertical direction to floor of the model, and the authors compared simulation result with experimental result. Simulation result shows the good agreement with experimental result; therefore the validity of the passenger model is verified.