The invention discloses a fast charging device for a storage battery system so that an alternating-current power supply and a storage battery pack are connected by the fast charging device and thus the rapid charging of the battery pack can be realized. An active filter, an alternating-current contactor and a three-phase rectifier bridge are connected based on phases successively; an input inductor and the input capacitor are connected in series and then are connected to positive and negative terminals of the output terminal of the three-phase rectifier bridge; the input terminal of an alternating-current conversion module is connected to the two ends of the input capacitor; and the output terminal of the alternating-current conversion module is connected to the input terminal of an isolation transformer. A high voltage direct-current relay, an output capacitor and a battery pack are connected in series; one end of the output capacitor is connected to the cathode of a diode rectifier bridge through an output inductor and the other end is connected with the anode of the diode rectifier bridge; and the output terminal of the diode rectifier bridge is connected to the output terminalof the isolation transformer. Therefore, charging efficiency of the battery is improved and the safety of the storage battery during the charging and discharging processes is enhanced.