Abstract: Aiming at the disadvantages of big volume,bulkiness,high cost of traditional mine charger of battery locomotive with phase control,the paper proposed a design scheme of mine charger of battery locomotive based on three-level DC-DC converter.It introduced working principle and implementation mode of main circuit and control circuit of the charger in details.The experiment result showed that the charger has advantages of small volume,light weight and low cost comparing with charger with phase control.