The negative effects of habitat fragmentation on wildlife are focused by global ecologists and conservation biologists. As one of major factors attributed to the loss of biodiversity, habitat fragmentation has become one of frontier and active issues in conservation biology and ecology in recent twenty years. Habitat fragmentation is a dynamic process including a wide range of spatial patterns of environments that may occur on many spatial scales. The ecological effects of habitat fragmentation on birds may show area, isolation and edge effects which will affect bird life finally. In this paper, I summarized habitat fragmentation process, theoretical models and its effects on bird life.