Technology of Geographic Information System (GIS) is used to segment port hinterland for the first time.To eliminate the influence of subjective factors and also considering randomness of shippers’ choices for ports,a density model is developed based on improved Huff model to measure the attraction of port by introducing the concept of grid in GIS.GIS software is first applied to figure out the model.Then,port of Dalian and port of Yingkou in northeast China are taken as a case to analyze the model by segmenting hinterland of the two ports respectively.The results are in accordance with actual situation basically,which indicates that the density model based on GIS is practically significant.