Tire contour design theory has always been studied because of its significant effect on tire performance. Based on the new non-natural equilibrium contour theory, the influence of belt pressure share ratio on the carcass contour is studied. The type of 385 / 65R22.5 all-steel radial tire was chosen as the research object and the finite element analysis technique was adopted to calculate the belt pressure share ratio. The results show that with the increase of the belt pressure share ratio, the clamping effect of belt layer on the carcass is strengthened, the curvature of tire crown in carcass contour increases and the crown curve tends to be rounded. The influence of belt pressure share ratio on wear, footprint, rolling resistance and grip performance was also explored with the finite element technology. It turned out that with the increase of the belt pressure share ratio, the tire wear increased, rolling resistance reduced, grip performance enhanced.