Abstract: In view of problems of low power supply reliability, poor anti-interference ability and inconvenient extension of backup battery capacity existed in coal mine underground distributed power supply, an integrated intelligent back-up power supply was developed, working principle and composition of the power supply were introduced in detail. The power supply has strong anti-interference capability, rapid diagnosis, rapid positioning function for over voltage, over current, short circuit fault .The power supply can prevent battery discharge, and provides reliable, economic, safe and uninterrupted power supply for all kinds of digital mine system.