A charging system, comprising: a power supply device comprising a first power transmission terminal, a second power transmission terminal, a first signal output terminal and a power control unit, wherein the first power transmission terminal receives AC power; a connection confirmation module comprising a second signal output terminal; a battery module; a charging module comprising a third power transmission terminal and a fourth power transmission terminal, wherein the third power transmission terminal is detachably connected with the second power transmission terminal of the power supply device, and the charging module comprises a DC/DC converter, a voltage regulator, a bus capacitor and a charging controller, wherein the DC/DC converter is a bidirectional power converter and is electrically connected between the bus capacitor and the fourth power transmission terminal, the fourth power transmission terminal is further connected with the battery module, an adjusting terminal of the voltage regulator is detachably connected with the first signal output terminal, the voltage regulator selectively adjusts a voltage of the adjusting terminal, and the power control unit detects a voltage of the adjusting terminal, and the charging controller receives a voltage of the second signal output terminal and the voltage of the adjusting terminal and detects a voltage of the battery module; and a main control module connected with the charging module and the second signal output terminal for receiving a feedback signal from the charging module and a signal from the second signal output terminal, characterized in that if the charging controller detects that the voltage from the battery module is non-zero and the voltage from the adjusting terminal is a given voltage when the charging module is connected with the power supply device, the charging controller controls the DC/DC converter in a backward direction to convert electric power from the battery module, so that the bus capacitor is pre-charged by the converted electric power of the battery module, wherein if the charging controller judges that a voltage of the bus capacitor is higher than or equal to a first threshold value, the charging controller controls the voltage regulator to adjust the voltage of the adjusting terminal toward a second threshold value, wherein if the power control unit detects that a peak voltage of the adjusting terminal is equal to the second threshold value, the power control unit judges that the charging system is ready to charge the battery module. a power supply device comprising a first power transmission terminal, a second power transmission terminal, a first signal output terminal and a power control unit, wherein the first power transmission terminal receives AC power; a connection confirmation module comprising a second signal output terminal; a battery module; a charging module comprising a third power transmission terminal and a fourth power transmission terminal, wherein the third power transmission terminal is detachably connected with the second power transmission terminal of the power supply device, and the charging module comprises a DC/DC converter, a voltage regulator, a bus capacitor and a charging controller, wherein the DC/DC converter is a bidirectional power converter and is electrically connected between the bus capacitor and the fourth power transmission terminal, the fourth power transmission terminal is further connected with the battery module, an adjusting terminal of the voltage regulator is detachably connected with the first signal output terminal, the voltage regulator selectively adjusts a voltage of the adjusting terminal, and the power control unit detects a voltage of the adjusting terminal, and the charging controller receives a voltage of the second signal output terminal and the voltage of the adjusting terminal and detects a voltage of the battery module; and a main control module connected with the charging module and the second signal output terminal for receiving a feedback signal from the charging module and a signal from the second signal output terminal, characterized in that if the charging controller detects that the voltage from the battery module is non-zero and the voltage from the adjusting terminal is a given voltage when the charging module is connected with the power supply device, the charging controller controls the DC/DC converter in a backward direction to convert electric power from the battery module, so that the bus capacitor is pre-charged by the converted electric power of the battery module, wherein if the charging controller judges that a voltage of the bus capacitor is higher than or equal to a first threshold value, the charging controller controls the voltage regulator to adjust the voltage of the adjusting terminal toward a second threshold value, wherein if the power control unit detects that a peak voltage of the adjusting terminal is equal to the second threshold value, the power control unit judges that the charging system is ready to charge the battery module.