The present invention provides an oil pumping unit alternating load loading controller used for a motor test, comprising a measurement simulation system consisting of an oil pumping unit motor, a direct current motor, a torque rotation speed sensor and a DSP electrical parameter measurement and acquisition circuit, and a DSP core control system, wherein the measurement simulation system is characterized in that the direct current motor simulates operating condition of the oil pumping unit to generate alternating load to be loaded to the oil pumping unit motor, and then electrical parameters of the oil pumping unit motor are measured; the DSP core control system controls the direct current motor to generate alternating load by taking the received electrical parameters of the oil pumping unit motor as feedback quantity. The oil pumping unit alternating load loading controller used for the motor test accurately simulates the real operating condition of the on-site oil pumping unit on the premise of ensuring measurement accuracy. The oil pumping unit alternating load loading controller used for the motor test overcomes the deficiency of a conventional oil pumping unit alternating load dynamic loading system, accurately simulates the real operating condition of the oil pumping unit load, and provides practical and effective scientific basis for performance evaluation of an oil pumping unit energy-saving motor.