This paper approaches to grade commercial land differential rent in cities based on Geographical Information System(GIS).Firstly,the three quantitative indexes of evaluating factor: commercial location,traffic condition and population density,are established separately in the support of the spatial database of land,traffic and population.Then,a unified evaluating index is created by using the model of discriminating geographic environment.Finally,the spatial database of commercial land rent class was established and primitive land plan was discussed according to the map of land rent class in the example of Putuo district,Shanghai.Meanwhile,a series of methods for extracting the data are developed by using PC ARC/INFO toolkits.The result shows that the study provides not only a valid means to appraise commercial land prices for land administration,but also the reliable basic data for urban planning.