Community building has gradually received great support in Taiwan's society. Incited by their identity to the land, history, culture and natural environment, people are more willing to participate in the public domain and create a new vision for their community. The feeling of alienation in some communities has gradually been reversed, and people try to reconnect themselves inside their communities. Nowadays, a few communities in Taiwan do have a substantive change because of citizen participation in their communities. In addition, the political and societal environments in Taiwan have also been progressively altered because of the power coming from the bottom---community. Nonprofit organizations (NPOs) have joined in the processes of community building and play important roles. NPOs can, on the one hand, supply their knowledge and expertise to local communities, and, on the other hand, receive resources from local communities. In addition, because of local communities' assistance, NPOs can be invited by the state to join the operation of the political system and become the representative of the local communities. The grievances, discontents, or intentions from local communities and the civil society therefore can be expressed by the NPOs in their contact with the state. They can exchange information received both from the local communities and from the state and become the important mediators. The NPOs therefore seemingly to have great impact on the community building. Above all, new social movement theories are employed in this paper, which also tries to apply a case study on the Homemakers' Union and Foundation in Taiwan to describe the impact of it on the community building.