Reverse power supply PoE switch adjusting electrical power automatically

The utility model relates to a reverse power supply PoE switch, in particular to a reverse power supply PoE switch adjusting electrical power thereof automatically. The reverse power supply PoE switch comprises a casing (1), a DC/DC step-down circuit module, a switch system module and a PSE power supply module, wherein the DC/DC step-down circuit module is respectively connected with the switch system module and the PSE power supply module, the casing (1) is provided with a PD port (2), and a PD port power identification circuit module and a PD circuit module are arranged between the PD port (2) and the PSE power supply module. By adopting the method, an MCU microcontroller module can read a power supply power value which can be provided by an output port of a higher PoE switch, thus the problem that the reverse power supply PoE switch cannot know the electrical power of the higher PoE switch is solved, and the problems that the PoE switch cannot use the electrical power reasonably and even cannot operate normally can be solved through the known electrical power.