Abstract: Three intelligent algorithms, GA (genetic algorithm), SAA (simulated annealing algorithm) and TSA (tabu search algorithm), were introduced in computing the QoS-based optimization multicast routing tree. A QoS-based high-speed network model was established to support QoS multicast. Then, the mathematical model for multicast algorithm problems was established based on the network model. The three intelligent algorithms and relevant key issues were analyzed with the solutions given to them when applying them to QpS-based multicast routing algorithms. Finally, the three algorithms were compared in terms of the request for network cost and runtime. The simulation shows that the three algorithms all have high performance and can meet the requirements for QoS multicast in NGI.