A wireless relay device and a wireless relay control system are provided. The wireless relay control system includes a wireless relay device and a mobile device carrier. The wireless relay device includes a power switch for controlling power supply to a vehicle, a relay communication module for performing wireless communication, and a relay processing unit for controlling the power switch and the relay communication module. The mobile device carrier is electrically connected with the wireless relay device and equipped with an application program including a biometric identification module for controlling a biometric identification function and an application communication module for controlling a communication function. The application communication module performs handshake with the relay communication module, and the biometric identification module verifies a biometric feature of a user to control the power switch to or not to supply power to the vehicle.