The behavioral-related environmental study for multifamily housing is needed to develop the quality of unit floor plan in terms of user comfort and needs. So, the aim of this study is to find out the living style and housing needs in terms of interaction between the users behavior pattern and orgarnization of physical home space. For the purpose, the field experiments in Pusan, have been carried out with 318 households living in apartments by plan types(2BL, 3BL, 4BL, 5BL) which were classified by number of bedrooms. The dwelling space usage behavior(room use pattern and furniture uasge pattern) and the space adjustment behavior(physical modification of space and preferred space adjustment attitude) were examined and analyzed.