The invention provides a method and a device for preventing an ARP (Address Resolution Protocol) attack. The method comprises steps: a network management server receives address binding information uploaded by a gateway device and corresponding to a gateway interface and address binding information corresponding to a terminal device, wherein the address binding information comprises a mapping relationship between an IP address and an MAC address; an address binding information table is created based on the address binding information, and the address binding information table is issued to each access switch; and after each access switch receives an ARP message transmitted by a target terminal device, and according to the address binding information table, the ARP attack is prevented. Through deploying the address binding information table items in a unified mode for the access switch by the network management server, automatic ARP attack prevention is realized, a large amount of manual operation in the prior art is reduced, the working efficiency is improved, and the problem of network congestion caused by the ARP attack can be effectively solved.