Abstract: Based on the conventional ride comfort model, an 11-DOF analysis model was developed with both the increasing of seats and the nonlinear factors of suspension damper taken into account. Considering the pitch-up/down and roll of the vehicle body, and the impact of seats on vehicle's ride comfort, the developed model involved more details. The vehicle body's vibration due to its vertical motion, pitch and roll and the four seats' vibration acceleration were obtained by the variable step integration. And the effects of different road surfaces, travelling speeds and sitting seats on vehicle's ride comfort were analyzed. The results showed that the 11-DOF analysis model developed for vehicle's ride comfort is more practical and accurate than evaluating just in accordance to vehicles body balancing.