Abstract: For characteristics that power supplys in coal mine underground has multi input voltage grades and are susceptible to disturbed when big equipments are starting or stopping, the paper put forward a design scheme of adaptive wide-voltage power supply with explosion-proof and intrinsic safety. The power supply uses intelligent phase shift voltage regulating technology and wide-voltage switching power supply technology, and adopts single-chip microcomputer to realize automatic identification of high and low voltage section, automatic switch, intelligent phase shift voltage regulating of 85-825 V wide input voltage, and uses PWM to convert fluctuant voltage to a stable DC voltage. The experiment results show that the scheme solves problems of multi voltage grades and wide-voltage fluctuation of mine-used power supply.