In order to quantify the effects of different seat cushion density on driver/passengers' sitting comfort, a 95th percentile human-body model that meets the Chinese physical structure and a driver/passenger-automotive seat model of different density were built，which simulated the driver/passengers' general body pressure distribution and body-parts' pressure distribution with different foaming density of automotive seats. The simulation results showed that this paper more precisely determined the variation rule of pressure distribution and shear force between seats with different foaming density and occupants, shortened the seats' research period, then quantitatively and delicately analyzed the impact of different seat cushion density on sitting comfort during the concept design stage before commissioning.