Downtown decay has been in focus in Europe, America and Japan, but in Taiwan it is still at the elementary stage in relation to policy development. Therefore, the analysis of real competitive difference between downtown trading areas and suburban trading areas is inadequate. In order to clarify the real competitive situation, this study firstly will survey the location and management characteristics of large scale trading areas in the metropolis of Tainan. Secondly, we will investigate one thousand households in order to discuss consumption preferences. Different characteristics of consumption behavior will be studied with respect to gender, age, educational background, and salary. Additionally, Factor Analysis and Cluster Analysis will be used to assess the importance to users of different aspects of the shopping experience, and thereby to measure the competition between downtown trading areas and suburban trading areas. This study will show the competitive situation of large scale trading areas in the metropolis of Tainan, and land use and business sprawl issues will be discussed.