Aiming at the wedge shape problem of rolling section that may occur in the hot rolling process of pure titanium medium and thick plate, combined with the asymmetric characteristics of four-high rolling mill equipment and technology., the elastic deformation model of double cantilever beam roll system is established based on the influence function method. The influence of asymmetrical factors such as the centring error, stiffness difference of mill stand, wedge shape of billet, transverse temperature difference of workpiece and other asymmetric deformation parameters on rolling section wedge shape are investigated. The results indicate that the effect of the above influence factors increase with the increase of the plate width and rolling reduction. The influence of the inlet wedge shape on the outlet wedge shape increases with the increase of the plate width and the decrease of the rolling reduction.