Although the nature and type of use of various public buildings are different, they can be divided into three parts: the main use part, the secondary use part (or auxiliary part) and the traffic connection part. In the design, we should first grasp the relationship of these three parts to for arrangement and combination, and solve various contradictions one by one in order to obtain the rationality and perfection of the functional relationship.  In the constituent relationship of these three parts, the allocation of traffic connection space often plays a key role.