In order to build the high accuracy mathematic model of hot roll strip profile,the influence ratio calculation software is developed with influence coefficients method,based on the theory of strip profile′s calculation. The ground value of special rolling force influencing ratio were calculated. The hexad polynomial fitting coefficients of special rolling force influencing ratio revised coefficients(revised by work roll diameter and back up roll diameter) were computed. The universal calculation model of special rolling force influencing ratio was built. The influence of special rolling force and roll diameters on hot roll diameters on hot roll strip profile were analyzed systematically. It is shown that along with the increasing of strip width,the changing curves of special rolling force influence ratio in 4 high mill change as parabola,the effect of work roll diameter and back up roll diameter on special rolling force influencing ratio play an important role. The simulation can be supplied for the strip profile control and the optimization of model coefficients.