The invention relates to an arc protection device of a medium- and low-voltage switch cabinet. The arc protection device comprises a device body, wherein the device body is arranged on the switch cabinet, a plurality of metal holes are formed in the device body and are uniformly arranged, a current acquisition module, an arc acquisition module, a processing module, a control module, a transmission module and a power module are arranged on the device body in an insertion way, the current acquisition module is used for acquiring a current signal, the arc acquisition module is used for acquiring an arc signal, the processing module is used for processing the signal, the control module is used for disconnecting the current, the transmission module is used for sending the processing information, the power module is used for providing power for the whole device, and the current acquisition module, the arc acquisition module, the control module, the transmission module, the power module and the processing module are electrically connected through connection wires. Compared with the prior art, the arc protection device has the advantages and effects that by matching of all modules, the arc protection of the medium- and low-voltage switch cabinet is further achieved, and the safety of the medium- and low-voltage switch cabinet is ensured.