The utility model discloses a hydraulic loop for controlling lifting of a hydraulic cylinder. The device comprises an oil tank, hydraulic pumps and hydraulic cylinders, when the hydraulic pump rotatesforwards, the hydraulic oil in the oil supply tank can be pumped out. the oil flows to a forward rotation oil inlet of the hydraulic pump through a first ball valve and a first one-way valve; then the oil flows to the hydraulic cylinder from a reverse oil inlet of the hydraulic pump through the hydraulic control one-way valve; the oil inlet path enables the hydraulic cylinder to ascend; when thehydraulic pump rotates reversely, the hydraulic oil in the oil supply tank is pumped out; the oil flows to a reverse oil inlet of the hydraulic pump through the first ball valve and the second one-wayvalve; then the oil flows to a control bypass of the hydraulic control one-way valve from a forward rotation oil inlet of the hydraulic pump; the reversing oil path enables the hydraulic control one-way valve to be opened reversely; when the hydraulic control one-way valve is reversely opened, the hydraulic oil in the hydraulic cylinder can flow out; the hydraulic oil flows back to a reverse oilinlet of the hydraulic pump through the hydraulic control one-way valve and then flows back to an oil return way of the oil tank from a forward oil inlet of the hydraulic pump through the first overflow valve and the filter to enable the hydraulic cylinder to descend, the hydraulic oil flow direction can be changed through forward and reverse rotation of the hydraulic pump, and therefore the hydraulic cylinder is controlled to ascend and descend.