Abstract: To solve the problems of long charging and discharging time, low efficiency, high cost, and poor reproducibility in the measurement and test of electric bicycle charging pile, avoid potential safety hazards caused by the use of battery and improve the detection efficiency and reliability of measurement results, a battery simulator based on STM32 and digital adjustable power supply is designed. The simulator consists of MCU control unit, digital adjustable power supply, sampling circuit, channel on/off and polarity switching circuit, programmable load, and other parts. The working principle, module composition, and software control flow of the battery simulator are introduced, and the test data are given. The test results show that the battery simulator has continuous and stable adjustable power supply output and adjustable load, which can better simulate the three-stage charging mode of the battery and meet the measurement and testing needs of the charging pile.