In this paper, we propose a systematic scheme of wavelength assignment for multicast in WDM network with sparse wavelength conversion nodes. The proposed scheme considers the generalized network environment when comparing to the literature , which assumed that all network nodes have no wavelength conversion capability. By using the concept of segmentation and grouping, the proposed scheme can be generally applied for the wavelength assignment of multicast in WDM network. Based on the foundation of the proposed scheme, three approaches, Minimum-Effect-First (MEF), First-Fit, and Random, are provided for the selection of wavelength. The efficiency of the arrangement of wavelengths is measured by its influences on the available capacity of the network. The performance of the proposed scheme is examined through exhaustive simulations and compared with the tipper bound. Our experimental results indicate that the proposed scheme can effectively minimize the affected bandwidth and the MEF approach is superior to the other two approaches.