Method for controlling reduction rate of last pass of finish rolling

The invention discloses a method for controlling the reduction rate of the last pass of finish rolling. The method comprises the following steps that (1), an L2 model generates the pass number according to production information; (2), the reduction rate of the last pass is adjusted to split the passes; (3), the reduction rate of the last pass is matched with the maximum rolling force; and (4), after a working roll is replaced, the rolling reduction rate in the early stage of roll forming is controlled to be 18%-12%, the rolling reduction rate in the middle stage of roll forming is controlled to be 12%-10%, and the rolling reduction rate in the later stage of roll forming is controlled to be 10%-8%. According to the method for controlling the reduction rate of the last pass of finish rolling, the change of the reduction rate of the last pass is quantified by utilizing the reduction rate control of the last pass, and the reduction rate is set through the input window, so that the pass can be set in place at a t