Abstract: Since the program of Beijing CBD was made,it has been the focus concerned by the people.Although the program is reasonable in overall view,there remain some inharmonious points and even serious problems that are hard to handle.This paper analyzes the relation between CBD and Sub-CBD,and puts forward some points on the CBD System Theory,on the basis of which this paper studies further the problems in development of Beijing CBD;finally it draws a conclusion that it is more reasonable to establish the CBD system than a single CBD in Beijing.