A new algorithm based ant colony optimization for QoS (quality of service) mobile multicast routing is proposed in the paper. According to the scope of search paths, a suitable orthogonal table of the orthogonal experiment is implemented, and the effect of every QoS parameter is confirmed. Meantime, An improved measure is taken to control the volatility of pheromone dynamically, and the optimal tree which satisfies the multiple QoS constraints is to be found. The experimental results show that the proposed algorithm can achieve the global optimal solution rapidly and meet multiple QoS constraints perfectly.