To study the effect of the vehicle's figure simplification on the vehicle's lift force, an 1∶1 scaled vehicle model was applied as the study object. Simulations for the vehicle with four different simplified figures were carried using CFD method. By comparing and analyzing the obtained results, the reasons for the differences among the four kinds of figures were found out. And the error ranges for them were provided. The results showed that in the early automobile design stage, to study the vehicle's lift force, the simplified figure of the vehicle could be used. Thus could save time and resource effectively and shorten the design cycle.