Abstract: In view of problems of low conversion efficiency, easy damage of switching devices and inapplicable to super capacitors of non-isolated converters currently used in mine electric locomotive, a parallel interleaved DC/DC converter applied to mine electric locomotive was introduced. At the low voltage side, a parallel interleaving structure is proposed to charge the capacitor and reduce current ripple; At the high voltage side, two capacitors are connected in series by adding a switch tube to increase buck-boost gain. Working process of the converter under boost drive mode and buck charging mode are described. The voltage/current double closed-loop step-up and constant current limit charging controller are designed. The experimental results show that the parallel interleaved DC/DC converter can effectively improve the performance of the electric locomotive in DC conversion.