The bounded shortest multicast algorithm(BSMA)is believed the best constrained multicast algorithm. However,the large computation time restricts its application.As a global optimizing algorithm,genetic algorithm (GA)is applied to solve the problem of multicast more and more.GA has more powerful searching ability than traditional algorithm,however its property of"prematurity"makes it difficult to get a good multicast tree.A quantum clonal algorithm(QCA)to deal with multicast routing problem is presented in this paper,which saliently solves the"prematurity"problem in Genetic based multicast algorithm.Furthermore,the algorithm is accelerated by using quantum crossover.The algorithm has the property of simple realization and flexible control.The simulation results show that QCA has a better performance than BSMA and traditional GA.