The invention relates to the technical field of strip steel rolling, in particular to a strip steel plate shape control method and a strip steel plate shape control device. The strip steel plate shapecontrol method comprises the steps of based on a convexity equation, setting an outlet convexity variable quantity of strip steel as zero, and obtaining a relation between a roll bending force variable quantity and roll bending force transverse stiffness; based on the relation between the roll bending force variable quantity and the roll bending force transverse stiffness, according to intermediate roll transverse stiffness, obtaining an intermediate roll bending force compensation value; based on the relation between the roll bending force variable quantity and the roll bending force transverse stiffness, according to working roll transverse stiffness, obtaining a working roll bending force compensation value; utilizing the intermediate roll bending force compensation value for compensating an intermediate roll bending force; and utilizing the working roll bending force compensation value for compensating a working roll bending force. According to the strip steel plate shape controlmethod and the strip steel plate shape control device provided by the invention, the setting accuracy of a rolling force can be greatly improved, the adverse effect caused on a strip steel plate shapedue to rolling force fluctuation is reduced, the mutation of the strip steel plate shape is avoided, the stability in production is improved, meanwhile, the production efficiency can be further improved, and the accident rate is reduced.