Routing strategy is one of the most important aspects in a mobile agent system, which is a complex combinatorial problem. Most of current mobile agent systems adopt static routing strategies, which don’t consider dynamic network status and host status. This is a hinder to the performance and autonomy of mobile agents. Ant Algorithm is good at solving such kind of problems. After analyzing existing routing strategies of typical mobile agent systems, this paper summarizes factors that may affect routing strategy of mobile agents, proposes an Ant Algorithm based dynamic routing strategy by using both experience and network environment such as resource information, network traffic, host workload, presents an acquiring and storing method of routing parameters and decision rules according to the major characteristics of mobile agent migration. The simulation experiment is implemented and the results show our dynamic routing strategy can effectively improve the performance and autonomy of mobile agents.