The present invention is to provide a PLC device, which includes a power receiving port connected to a power supply for receiving a power signal and a network signal carried by the power signal; a filtering unit having a first end connected to the power receiving port; a power output port connected to a second end of the filtering unit and a load, respectively, for supplying the power signal to the load while the filtering unit filters out noise generated in the power signal by the load; a switching unit having two connecting ends connecting to the first and second ends, respectively, and a control end switchable between the two connecting ends; and a processing unit connected to the control end and including a bridge module for receiving and then transmitting the network signal to a network apparatus, and a detection module for detecting the level of the noise.