The invention relates to a POE power supply system and a self-recovery lightning protection device thereof. The self-recovery lightning protection device comprises a first communication interface, a second communication interface, and a self-recovery lightning protection circuit connected to the first communication interface and the second communication interface. The self-recovery lightning protection circuit comprises a signal protection circuit and a power protection circuit. The signal protection circuit comprises a first-stage bleeder circuit and a first self-recovery circuit connected with the first-stage bleeder circuit. The power protection circuit comprises a power bleeder circuit and a second self-recovery circuit connected with the power bleeder circuit. Through double lightningovervoltage protection provided by the signal protection circuit and the power protection circuit of the POE power supply self-recovery lightning protection device, the purpose of protecting the POEpower supply system is achieved, the performance of protection to the POE power supply system is improved, and the anti-lightning-stroke safety and reliability of the POE power supply system are high.The first self-recovery circuit and the power bleeder circuit are automatically restored to normal under the condition of having no lightning stroke voltage, and convenience is provided for users.