The wavelength assignment with multiple multicast requests in fixed routing WDM network is studied.A new multicast dynamic wavelength assignment algorithm is presented based on matching degree.First,the wavelength matching degree between available wavelengths and multicast routing trees is introduced into the algorithm.Then,the wavelength assignment is translated into the maximum weight matching in bipartite graph,and this matching problem is solved by using an extended Kuhn-Munkres algorithm.The simulation results prove that the overall optimal wavelength assignment scheme is obtained in polynomial time.At the same time,the proposed algorithm can reduce the connecting blocking probability and improve the system resource utilization. The wavelength assignment with multiple multicast requests in fixed routing WDM network is studied. A new multicast dynamic wavelength assignment algorithm is presented based on matching degree. First, the wavelength matching degree between wavelengths and multicast routing trees is introduced into the algorithm. the wavelength assignment is translated into maximum weight matching in bipartite graph, and this matching problem is solved by using an extended Kuhn-Munkres algorithm. The simulation results prove that the overall optimal wavelength assignment scheme is obtained in polynomial time. At the same time , the proposed algorithm can reduce the coupling blocking probability and improve the system resource utilization.