An identity verification method, an IoT gateway device, and a verification gateway device using the same are provided. According to the provided method, the IoT gateway device firstly establishes a look-up table including a valid MAC address list and a valid RSSI range of at least one valid client device. When the IoT gateway device receives the connection request sent from the client device, the IoT gateway device may obtain the MAC address and a RSSI value of the client device according to the connection request and compare the received MAC address and the received RSSI value with the valid MAC address list and the valid RSSI range, so as to determine whether the client device is the valid client device.