Abstract: The calculation module of influence coefficient method under asymmetrical condition was developed based on the dual cantilever theory to research the regularity of the effect of incoming wedge on lateral curvature of plate, as well as enhance the control efficiency and accuracy of lateral curvature for a domestic plate rolling 4-high mill. The roll and work piece discretizing method, the decision of key mathematic model, vectors and arrays were described. Using the calculation module, the calculation was carried out based on actual data in-site. The regularity of effect on radius of curvature was obtained, the rigid titling of rolls is indicated to be effective method to control lateral curvature. The mathematic models of target wedge and curvature control when the incoming plate is wedge-shaped were also built.