This research examines the communitization of two Buddhist groups, the Compassion Relief Tzu-chi Foundation and the Dharma Drum Foundation, by looking at the social background, belief needs and practices, and net workings of their members. The research goal is to develop theories about the foundation, function and meanings of Buddhist communities, which is not centered around the temple but oriented toward social services and education, in contemporary Taiwanese society. The author observes that group members vary in their age, gender, and social status. Accordingly, the religious appeal of charity and spiritual cultivation often engender "non-religious" socio-psychological functions and meanings in individual practices. However, the sacredness of the leaders' character as perceived by their followers, and of the group rituals and language help to solidify members' group identity. In addition, these Buddhist communities draw upon the symbol of "big family" to invoke members' loyalties and pieties to their leaders. Many families also participate in these communities by virtue of donation, volunteer work and touring some programs.