Power over Ethernet (PoE) control method, power sourcing equipment (PSE) and system

The invention provides a power over Ethernet (PoE) control method, power sourcing equipment (PSE) and a system. The PoE control method comprises the following steps: in a time period when power supply is stopped, acquiring a medium access control (MAC) address of an access point (AP) of a wireless local area network (WLAN) which is connected through a PoE port by using the power sourcing equipment; determining whether a user is online on the AP or not according to the MAC address; and stopping supplying power to the AP on which no user is online. According to the PoE control method provided by the embodiment of the invention, the PSE automatically identifies the working state of the AP according to the MAC address of the AP which is connected with the PSE in the time period when power supply is stopped; if the user is online, the PSE can continually supply power to the AP through the PoE port of a PoE system; and if no user is online, the PSE stops supplying power to the AP, so that the flexibility of the PoE control method is enhanced.