The invention provides an upper roller balance device of a rolling mill. The rolling mill comprises a pair of uprights facing each other, an upper roller and a lower roller horizontally arranged between a pair of uprights, and an upper adjusting cylinder and a lower adjusting cylinder controlling the pressing down and pressing up of the upper roller and lower roller respectively, wherein the upper adjusting cylinder and the lower adjusting cylinder are mounted on the inner upper side and the inner lower side of the uprights respectively. The upper roller balance device of the rolling mill comprises balance cylinders, a pneumatic control system and a hydraulic control system, wherein the balance cylinders are vertically mounted on the two sides in each upright and symmetrically support the upper roller; each balance cylinder comprises a rod cavity and a rodless cavity; the pneumatic control system is connected with the rod cavity to control high-pressure gas to flow in or out of the rod cavity; the hydraulic control system is connected with the rodless cavity to control hydraulic oil to flow in or out of the rodless cavity; and the hydraulic control system and the pneumatic control system control the movement of the piston of the balance cylinders to be consistent with the movement of the upper roller so as to realize the balance effect of the balance cylinders on the upper roller. The balance device can adapt to bad working conditions to realize automatic control.