A power supply system having a wireless security module for vehicles is provided. The power supply system comprises a battery module, a power management module, an energy management module and the wireless security module. The battery module powers a starting motor of a vehicle. The power management module is used to receive a power from a power generating device. The power management module transmits the power of the power generating device into the battery module. The power management module comprises a monitoring unit and a controlling unit. The monitoring unit is used to monitor a voltage value of the battery module. When the voltage value monitored is equal to a minimum setting, the power management module is used to prevent the battery module from powering the starting motor. When the voltage value monitored is equal to a maximum setting, the power management module stops powering the battery module. The controlling unit is used to control a current value outputted from the battery module. Furthermore, when the voltage value of the battery module is equal to the maximum setting, the energy management module is used to receive a power from the power generating device. The power is transmitted into the vehicle by the energy management module.