Under the concept of sustainable development, the assignments of architectural programming should not be concentrated on composition of buildings only, but also be extended to the outcome of the programs to environment, furthermore to provide a positive impact to it. Among various dwelling types, collective housing can afford greater quantity of habitable units, better management as well as increase the efficiency of land usage and decrease the interference of the unused land. That makes it belonging to one of the more sustainable dwelling types. In the high densely occupied island Taiwan, collective housing is just the most popular dwelling form that should promote the sustainability of residential environment. Unfortunately, residential behavior and requirements of dwellers are less concerned in practice, so that the users often have to rebuild their new houses to fit daily life. This unsustainable phenomenon of a sustainable dwelling type indicates that negligence of behavioral requirement by architectural programming for collective housing exists. Hence a suitable architectural programming considering an appropriate size and also behavioral requirements of residents at the same time could solve the problem. This study would try to discus the size and the usage of collective housing in four metropolises Taiwan’s, Taipei, Taizhong, Tainan and Gaoxiong, in last ten years. Under the premises of satisfaction with dwelling behaviors of residents, the sustainable factors would be found out to understand the relationship between sustainability and dwelling behavior in Taiwan. Method of this study is based on the post-occupied evaluation (POE) intending to inspect some behavioral issues of housing programming under the influence of sustainable development. Through statistical analyses of data surveyed the influence factors, such as ”family characters”, ”usage behavior” and ”consideration of sustainability”, onto dwelling size would be figured out. Using correlation analysis as well as principal component analysis, the structure of influence factors to dwellings size of collective housing would be discovered. This study could contribute to the sustainability of Taiwan by establishing a model of appropriate dwelling size for collective housing. Consequences of the research would as follow: 1. Represent the influence factors of dwelling size, and how they affect the size of individual spaces in a dwelling unit. 2. Build up a regression model by taking the influence factors as independent variables and the size of individual spaces in a dwelling unit as dependent variable. Using this model, dwelling size could be adjusted to an appropriate situation according to the requirements of usage and characters of the residents. 3. Variegate the sizes of individual spaces in a dwelling unite under a fixed size of dwelling unit. 4. Compare the investigated data with the appropriate value calculated from the model to illustrate the difference between the actuality and ideal of the sustainable dwelling size of collective housing in Taiwan.