The invention provides a hydraulic oil supply system for a rolling strengthening machine tool for a tooth root of a torsion shaft. The hydraulic oil supply system comprises a control unit, a motor pump assembly, an air cooler, a temperature transmitter, a heater, a check valve, a pressure sensor, an air filter, a coarse filter, a fine filter, a stop valve, an energy accumulator, an electric-hydraulic proportional pressure relief overflow valve, a pressure gauge, a pressure relay, a reversing valve, a digital display meter, a liquid level relay, a hydraulic chuck, an oil tank and the like. According to the hydraulic oil supply system provided by the invention, a pressure of oil output by a hydraulic station is accurately controlled through the electric-hydraulic proportional pressure reliefoverflow valve, the change of the pressure can be adapted in a large range, and an overflow function is achieved, so that the safe working of the hydraulic station is ensured; the electric-hydraulicproportional pressure relief overflow valve is adopted, and is not inferior to servo pressure adjustment in accuracy, and low in cost, so that requirement on the cleanliness of the oil is reduced; andin addition, the energy accumulator is used for maintaining the pressure, so that lots of heat generated due to pump running is reduced to a great extent, and energy conservation is realized.