According to the power demand of portable Raman spectrometer, a small volume, digital power management system is designed.This power management system takes STM32 as the main control chip, adopts TI company's battery management chip BQ3060 and BQ24005 to realize the management of lithium battery, designs the power supply switching module and switch control module to control the double power supply switching and the system switching machine, and uses the DC/DC conversion module to ensure the constant voltage output of the system.Finally, through software programming, the system can inquire the power supply status in real time and adjust the power supply strategy. After debugging the power management system with small Raman spectroscopy system as the load power supply test, the results show that the system’s power supply , small temperature change range, feedback can real-time management of power supply and power supply condition meet the design requirements.This system provides a good solution for portable Raman spectrometer power management system.