An analysis on the factors which affect the layout of post offices is made. Research on the laws of distribution of post offices in cities is done. The method of determining the number of post offices and the layout of post offices in a new area of a city are put forward in this paper. An analysis on the factors which affect the layout of post offices is made. Research on the laws of distribution of post offices in cities is done. The method of determining the number of post offices and the layout of post offices in a new area of ​​a city ​​are put forward in this paper.