A network communication device includes a processor, an amplifier circuit, a matching circuit including a transmitting route and a coupling route, a storage module, and a detection and control module. The network communication device generate electronic signals, and outputs the electronic signals to a load via the transmitting route after the electronic signals being amplified and matched. Then the network communication device detects output signals and reflection signals of the coupling route to calculate a safety parameter accordingly, compares the calculated safety parameter with one or more safety parameter thresholds, and generates control signals to control the amplifier circuit. The network communication device determines if the load is abnormal according to the control signals and generates load abnormal signals if the load is abnormal.