关键词: 移动代理, 分布式拒绝服务攻击（DDoS）, 检测, 防御

Abstract: The attack of Distributed Denial of Service（DDoS） has become one of the most harmful problems in network security.There are some limitations in traditional defendant for using the single method.This paper proposes an initiative defence model which adopts mobile agent and integrate multi-defense methods.The elements of the mobile agent in defense model are designed in detail to solve the limitation of the single defense method，passive defense and high false alarm.The model is robust and scalable.

Key words: mobile agent, Distributed Denial of Service（DDoS）, detection, defense