Abstract: A mature subject must have its logic point, i. e., the key problem that should be solved by the subject in general. The paper first summarizes the logic point's concept and connotation, then the discusses the logic points of Architecture, Landscape Architecture and Tourism respectively to be 'shelter', ' plant'and ' move'. Therefore, the difference of the three subjects is to solve the three fundamental problems of human beings'living at different scale, namely, 'dwelling', 'work and rest' and 'locomotion'. The common purpose of them is to satisfy the survival and living need of people and to supply healthy and beautiful environment for human beings from different scale, furthermore, to improve people's living standard and to make their lives better. At last, based on the Tourism's logic point— 'move', the paper puts forward that the subject system of Tourism should include three aspects: planning and designing, reservation of nature and culture, and management.