In recent years, vehicle technologies for speed up and improvement of ride comfort had been developed. However, it was confirmed that vibrations around 10Hz and 30Hz were activated during high-speed running on the vehicle floor. Many studies for reducing vibration about 10Hz were performed, because vibration of these frequency area was big during normal speed running. Moreover, passengers were sensitive for low frequency vibration. As representative example of method for reducing vibration about 10Hz include to raise the rigidity of vehicle body. On the other hand, studies about reduction of vibration around 30Hz was not performed because there was little influence on the ride comfort in normal speed. But now, vibrations around 30Hz has become the big problem for the ride comfort. Therefore design guideline for developing a seat which restrain the vibration and improve ride comfort was desired. This study aims for investigating the vibration characteristics of a high speed railway vehicle seat and suggesting design guidelines for developing a seat which improve ride comfort by constructing a seat model which reproduces the vibration characteristics. Vibration tests were carried out and it was revealed that elastic oscillation occurred in a seat base and vibration properties were very complex. Then, the chair model was proposed using Multi Body Dynamics and some vibration properties were reproduced. However, some undesired vibration occurred so the model needed further investigation.