The invention discloses a confining pressure keeping system of a rock triaxial creep testing machine. In the system, a hydraulic pump is connected with a motor, an oil tank is connected with the inlet opening of the hydraulic pump via an oil filter, a relief valve is arranged between the outlet opening of the hydraulic pump and the oil tank, a servo change valve is respectively connected with theoil tank, the hydraulic pump, a double-stroke pressure cylinder and a check valve, the double-stroke pressure cylinder is internally provided with a limit sensor and is connected with the check valvein turn, the check valve and the oil line of the check valve connected with a triaxial chamber are respectively provided with an accumulator, a pressure gage and a pressure sensor, and the triaxial chamber is connected with the hydraulic pump via a stop valve and is connected with the oil tank via the stop valve. The invention has simple and convenient oil charging/discharging operations, and canmaintain the pressure in the triaxial chamber to be constant in a long term, thus greatly improving the testing precision and effectively prolonging the service life of a hydraulic element.