The invention relates to a complete roll forming configuring method for a wide flat steel hot rolling finish mill set. According to the characteristics that an upstream machine frame controls the convexity and a downstream machine frame controls the flatness in the seven-machine frame and four-roll hot rolling wide flat steel finish mill, a finish rolling inlet machine frame F1 adopts negative convexity working roll forming, a machine frame F2, a machine frame F3 and a machine frame F4 adopt cubic CVC working roll forming, and a machine frame F5, a machine frame F6, and a machine frame F7 adopt negative convexity working roll forming of sine curves and are matched with periodic roll shifting of the working roll with long stroke. The supporting rolls of all the machine frames of the finish mill set adopt positive convexity roll forming of sextic polynomes. The method improves the transverse rigidity of the machine frames of the finish mill, improves regulation and control efficiency of roll bending force of the working roll, and reduces flexibility deformation of the roll. The roll forming configuring method for the finish mill set improves stability of the wide flat steel rolling, reduces the deflection amount of the wide flat steel, prolongs the planned length for rolling and greatly improves profile shape control precision of the wide flat steel.