The invention provides a method, device and system for processing DNS behavior. The method comprises: resolving received network data packet; judging a DNS behavior type corresponding to the network data packet according to the resolution result; determining a processing body according to the DNS behavior type, wherein the processing body comprises a kernel and/or an application layer; and transferring the network data packet to the determined processing body, and processing the network data packet by the determined processing body. The method in the disclosure can improve the DNS defense capability, while improving the service processing capability of a single machine.