Optical multicast traffics need to con sume a large number of wavelength division multiplexing (WDM) optical network ba ndwidth resources.and the gap between the bandwidth capacity offered by a wavele ngth and the bandwidth required by the multicast request is very large.So,traffi c grooming is an effective method adopted to reduce the traffic request blocking probability and to improve the utilization of wavelength bandwidth resources fo r optical multicast networks.A novel optical multicast traffic grooming node arc hitecture with two-level switching is proposed in this paper.The traffic groomi ng port first algorithm (TGPFA) and the traffic constructing the new light-tree first algorithm (TCLFA) are researched for the architecture respectively to red uce the traffic blocking probability.Moreover,an adaptive dynamic multicast groo ming algorithm (ADMGA) based on TCLFA and TGPFA is brought forward to adapt to t he network available wavelength resources dynamically.By setting a threshold fun ction cprresponding to the network available bandwidth.the ADMGA algorithm can s elect the appropriate method to groom the new arriving multicast traffic request to the assigned wavelength with residual bandwidth.The simulation analysis and results show that the proposed ADMGA algorithm can reduce the request blocking p robability,decrease the bandwidth blocking ratio and improve the wavelength band width utilization for the WDM network with limited wavelength bandwidth resource .