A network device includes a power system, a processor, a power sourcing equipment PSE chip coupled to a first forward power supply port, and a first powered device PD chip coupled to a first reverse power receiving port. A first powered device is connected to the first forward power supply port and the first reverse power receiving port. When detecting that a power failure occurs on the network device, the processor instructs the first PD chip to draw power from the first powered device; the first PD chip draws the power from the first powered device through the first reverse power receiving port, and supplies the obtained power to the power system. Therefore, when a power failure occurs, the network device can continue to obtain power and work properly when the power failure occurs.