Abstract: For problems of existing mine-used flameproof and intrinsically safe type power supply with multiple input voltage level such as large voltage fluctuation, heavy weight and difficult maintenance, a design scheme of mine-used power supply with super wide input voltage range was put forward. The power supply uses a combination of Buck topology and Flyback topology, and can convert super wide input voltage of AC80-900 V to a stable DC voltage. Experimental results show that the power supply has strong anti input fluctuation performance, stable output voltage, low ripple and high efficiency.