The invention discloses a hydraulic oil supply system for an automatic transmission, and belongs to the technical field of automatic transmissions. The hydraulic oil supply system for the automatic transmission is high in efficiency on the basis that requirements of the transmission are met, and oil consumption of a vehicle is reduced. The hydraulic oil supply system for the automatic transmission comprises a main pump and a control oil pump; the two constant delivery pumps respectively supply oil for a hydraulic torque converter and a shifting control system, so that power consumption of the hydraulic oil supply system is reduced. When the flow rate of the main pump is higher than that of the control oil pump, a part of hydraulic oil of an oil circuit A flows into the control oil pump, another part of the hydraulic oil of the oil circuit A flows back to an oil suction port of the main pump via a pressure regulating valve, and the hydraulic oil is supplied for the shifting control system after the oil of the oil circuit A is sucked by the control oil pump. The hydraulic oil supply system has the advantage that the power consumption of the hydraulic oil supply system is low as compared with a hydraulic system with a single pump during operation under identical conditions.