A power detecting circuit for a power supply module is disclosed. The power detecting circuit includes a current detecting module, a micro control unit (MCU), a correcting circuit. The current detecting module is electrically coupled to the power supply module and configured to detect an output current value of the power supply module. The micro control unit (MCU) is electrically coupled to the current detecting module. The correcting circuit is electrically coupled to the MCU and configured to correct the output current value of the power supply module. The MCU is configured to calculate an output power value of the power supply module according to the output current value and a preset output voltage value or a tested output voltage value of the power supply module and display the output power value via a display module.