Habitat network as part of ecological networks is very important for species. Consequently, it is necessary to find out the impacts of land use change on habitat network as well as the dispersal and migration of species, especially in current rapid urbanizing condition. The research results will be a great contribution to rebuilding and optimizing regional ecological network from the perspective of species conservation and ecological process, but not only the landscape structure as most previous research did. The aim of the paper is to find out: (1) how to map out the habitat network of a certain species from TM images in a grid pattern? (2) How land use change affected the habitat network of the species, especially from the views of habitat patch and network structure? The Su-Xi-Chang Area of the Yangtze River Delta Area was selected as case study due to its rapid urban development and land use changes. In this research, the Egretta garzetta was selected as a regional representative species for the following three reasons: (1) marshland birds are the superior species among wild animals of the study area; (2) Egretta garzetta is the superior species among marshland birds which is on the list of Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES); (3) the data related to living and hunting habitats of Egretta garzetta in the study area are easy to get. Based on the study of the Egretta garzetta habitat, we developed a Conceptual Constraint Model of Species Habitat Patch (CCMSHP) and a method to select habitat patch properly from different land types. In CCMSHP, factors which affect the forming of species habitat were classified into three categories coarsely, which are physical, biological, and human disturbances. In each category, main specific constraints were obtained from previous results and transferred suitably from the calculation supported by the ArcGIS software. Based on the identified Egretta garzetta habitats, their habitat networks were accordingly developed. Then, landscape metrics and network structure indicators were applied to analyze the effect of land use change on the mapped-out habitat network. The results showed that: (1) the total area of patches suitable for Egretta garzetta's living and hunting was increased during the period from 2000 to 2010; however, the quality of the habitat network was decreased seriously due to the strong negative effect of newly-built constructions, such as expressways and high-speed railways. (2) The habitat network of Egretta garzetta is only a small part of the whole area which consists of four separate fractions. They were Yixing-Liyang Part, Binhu Part, Wuzhong Part, and Yangchenghu Part and ranked down respectively, according to their conditions of 2000. During the recent ten years, these fractions have been seriously destroyed. Among of them, Yixing-Liyang Part was in the worst condition and then following by Binhu, Wuzhong and Yangchenghu Part. In a summary, during the past ten years, the condition of Egretta garzetta habitat environment was becoming worse; and the land use change has affected the survival of Egretta garzetta badly. We suggest that the protection both of high and low-level patches in hierarchy is important and it is necessary to identify and rebuilt those disappeared low-level patches to improve the quality of habitat network.