Abstract: For problems of existing mine-used power supply such as inconvenient access, large volume, poor anti-fluctuation ability, complex circuit and high cost, a mine-used adaptive power supply with super wide input voltage range was designed. The power supply adopts input-series flyback converter, which can reduce voltage stress of power switching tube and convert super wide input voltage into stable DC voltage. The test results show that when input voltage is AC85-900 V, the maximum error of power supply output voltage is only 1.1%, ripple voltage is not more than 139 mV, and efficiency is 87.4%. In test of insulation withstand voltage, leakage current is not more than 1.53 mA and insulation resistance is not less than 50 MΩ, which meet explosion-proof requirements of GB 3836.4-2010 Explosive atmospheres Part 4: Equipment protection by intrinsic safety "i".