The invention relates to modification of a rolling mill, particularly relates to a rolling mill correcting method, and provides a rolling mill inclination and skew correcting method. The rolling mill inclination and skew correcting method comprises the following steps: measuring a mounting locating basis for a new rolling production line, determining a reversible type rolling mill center line of key equipment and a processing center surface of a window of a frame, and measuring rolling mill inclination and skew amount to determine a correcting scheme; mounting a lifting device of a rolling mill; arranging stable lifting towers on two sides of the rolling mill to guarantee center lines of the towers to be superposed to the center line of the frame; using a lifting tool beam combined to the frame, and enabling the whole frame of the rolling mill to ascend and descend by using a hydraulic hoisting system device, wherein a safe supporting cushion block is used for guaranteeing safety in a process; and breaking and removing a damaged grouting layer after hoisting, treating foundation bolts, rearranging a bed-mortar base plate, aligning a bottom plate, correcting the rolling mill, pretightening the foundation bolts, carrying out secondary grouting construction, and finally screwing down the foundation bolts. By the method, the damaged rolling mill can be repaired.