Abstract: At present,the structure of mining power supply with wide input voltage range is complicated,the voltage stress of switching tube is high,and the conversion efficiency is low. In order to solve these problems,a design scheme of mining series connection flyback converter was proposed. This scheme used a flyback converter to simplify the circuit, adopts a series connection of four-stage flyback converters to reduce the voltage stress on the switching tubes. At the same time,the negativefeedback control system was established and the type II compensator is used to improve the conversion efficiency,and the circuit protection mechanism of the isolation components of the power supply was added to ensure the reliable isolation of the mining power supply. The test results show that under the input voltage condition of 1 300 V,the voltage across one-way switching tube is only 521 V,which is lower than the withstand voltage of the switching tube,with a 30% margin left. The maximum error of the power output voltage is only 0. 5%,and the peak-to-peak value of the periodic and random offset does not exceed 114 mV, and the power conversion efficiency is as high as 91. 6%. The maximum leakage current in the voltage-withstand test is 1. 624 mA,and the insulation resistance is not less than 50 MΩ,meeting the the relevant standard requirements.