A power supply test circuit comprises a test unit and a conversion unit. The test unit comprises a first connector, a second connector, an induction resistor, a controller and an electronic switch. The conversion unit comprises a conversion chip and a third connector. A first terminal of the electronic switch is connected with the first connector via the induction resistor, a second terminal is connected with a control pin of the controller and a third terminal is connected with the second connector. Two input pins of the controller are connected with two ends of the induction resistor. Two input pins of a convertor are connected with two output pins of the controller and two output pins are connected with the third connector. The controller acquires a voltage value on the induction resistor, converts the voltage value into a current value and then provides to the conversion chip. The conversion chip converts the current value into a SMBUS signal and then outputs to monitoring equipment through the third connector so as to display, outputs a control signal through the control pin and controls conduction of the electronic switch so that an output voltage of the power supply is provided to a mainboard. Through adjusting a load on the mainboard, the mainboard is matched with the power supply.