Abstract: For problems of bulky, low charging efficiency, low input power factor and so on of traditional charger for mine-used lead-acid battery, a new type of smart charger was developed. The charger is composed of multi-link voltage power units, achieves continuous and adjustable transformation from input three-phase AC voltage with two standards to DC voltage of 0-300 V and current of 0-120 A through phase shift control of square wave pulse of IGBT inverter. Experimental results show that the charger achieves three-stage operating mode from constant current to constant voltage and then to float charging, the voltage and current are relatively stable; electrolyte density reaction of the battery group is stable without bubbles, and the temperature do not change obviously in the charging process.