Abstract: This paper deals with the multi-power management system for seafloor observation platforms. The master controller uses ST's 32-bit ARM core microprocessor STM32F103 in the system, which not only controls the multiple battery input and output, but also realizes automatic switching between the main and the stand-by powers. The MCU will judge and deal with the data of the voltage and current from the battery and load obtained by A/D module. The battery supplies power in an order of priority and the ON/OFF of output is intelligently controlled by MCU. The PC application software is used to real-time monitor the voltage and current of the battery and load as well as status of ON/OFF channels.