Embodiments of the present invention disclose a power line communications device, and the power line communications device includes a USB interface, a protocol conversion module, a signal conversion module, a coupler, and a power line interface. A first end of the USB interface is connected to a first end of the protocol conversion module, a second end of the protocol conversion module is connected to a first end of the signal conversion module, a second end of the signal conversion module is connected to a first end of the coupler, and a second end of the coupler is connected to a first end of the power line interface. During implementation of the embodiments of the present invention, the USB interface may be used to provide a network signal for a terminal device.