Abstract: In view of problem of mine-used portable gas detector using battery for power supply that battery has limited capacity, and bad contacts can affect battery charging effects, design scheme of wireless charging device for mine-used portable gas detector based on wireless power transmission technology was proposed. Wireless power transmission circuit converts DC power to high-frequency AC electromagnetic wave signal, and transmits it into the air through coil. Wireless power receiving circuit couples electromagnetic wave signal in the air through coil, and converts it to DC signal by rectifier filter, so as to provide power to mine-used portable gas detector. The test results show that the device can output stable DC voltage and has high transmission efficiency.