Abstract: A new QoS anycast routing algorithm based on an ant colony algorithm is proposed in this paper. In order to search a reasonable anycast routing path, a felicitous estimate method of the optimization path is designed and the load balance is considered. By adjusting the pheromone in the iteration-best path and re-initializing the algorithm, the proposed algorithm can efficiently avoid falling into local optimal and it can enlarge global searching. The results of the simulating experiment show that the algorithm can effectively find the global-best solution that satisfied the QoS constraint and balance the load of networks, and also can be utilized to satisfy the need of the clients for bandwidth, delay and cost on the basis of resource reservation.