This article shows that,from the process of humaninhabitation in a region,from the main conditions to form river portsand mountainous towns and from the formation process,from river streetto riverside road,the water street is the embryo of river port formation.The cities along Changjiang are all set up and flourished by ports.Thisexplains the importance of port and city river line.Two examples ofriverside road planning of a small riverside town are given.