Abstract: River features in spatial database are normally organized with directed graph,which lose the semantics of rivers and their regional character.This paper proposes a method to classify the river networks in spatial database,based on some factors of river characters.Firstly,the style of river networks and its character are described.Then,some factors to classify the river networks are presented,followed with a classification method and its process for river networks.After that,the data organization based on directed graph is discussed,also with an experiment of the classification.At last,a conclusion is drawn and the future work is planned.