A charger with over-voltage and over-current protection and a method for using the same are provided. The charger comprises a first interface, a second interface, a voltage stabilizing unit, a control unit, an input voltage sampling unit, a switch unit, and a current sampling unit. The voltage stabilizing unit receives an input voltage of an external power supply and provides a constant working voltage to the control unit. The input voltage sampling unit detects the input voltage real-timely. The current sampling unit detects charging current of the battery rod real-timely. The control unit determines whether the input voltage detected by the input voltage sampling unit generates over-voltage or not, or determines whether the charging current detected by the current sampling unit generates over-current or not, and controls the switch unit to turn on or turn off according to the determination results.