Abstract: Aiming at the problems of cumbersome factory inspection steps, low inspection efficiency, and poor consistency of protection parameter measurement results for intrinsically safe power supplies used in mining, a high-precision fully automatic factory inspection device for intrinsically safe power supplies has been designed, which has the functions of automatic detection and display of overvoltage protection parameters, overcurrent protection parameters, protection interval time and protection recovery process, and automatic switching of detection positions. A fully automatic detection method based on pulse width modulation (PWM) to automatically adjust the input voltage and analog load impedance of the intrinsically safe power supply for mining is proposed through research on the protection methods, overcurrent protection, and overvoltage protection mechanisms of the intrinsically safe power supply for mining, and combined with the characteristics of timed starting of the cut-off intrinsically safe power supply for mining. An intrinsically safe power supply module with adjustable output was designed using DC/DC chips; a resistive adjustable electronic load was designed using insulated gate bipolar transistors (IGBT); the switching of protection levels was achieved through relay control. According to the conventional testing methods for intrinsic safety power supplies, an automatic testing process for intrinsic safety power supplies has been designed and optimized, and the testing process is uniformly scheduled through an embedded microcontroller. By using two PWM signals and filtering them to generate two continuously variable DC voltages, the intrinsic safety power supply voltage and the conduction depth of the electronic load IGBT are controlled separately. Real time data acquisition is carried out by combining high-precision analog-to-digital converter (ADC) modules to measure the input voltage value at the moment of overvoltage protection and the input voltage, output voltage, and output current value at the moment of overcurrent protection, achieving the detection of overvoltage protection value, overcurrent protection value, output voltage deviation value by using the internal timer of the microcontroller to calculate the protection interval time and display the test results on the LCD screen. Compared with conventional testing methods, the inspection efficiency has been improved by 300%, manual participation has been reduced by 1000%, and the deviation of test results is less than 1%, effectively ensuring the consistency and reliability of intrinsically safe power supplies for mining.