Integrating a Geographic Information System (GIS) with an expert system can overcome the deficiencies of each system. This paper illustrates the integration of a GIS with an expert system in order to find the suitability rating of seven crops (maize, cotton, barley, soybean, tobacco, wheat, and rice) for the Kor and Sivand Sub-basin. Although GIS can perform various analyses like overlaying, buffering, and etc., but it does not have the tools to analyze multiple interrelated factors. On the other hand, expert systems can carry out various analyses but they cannot consider georeferenced information. Land evaluation is a vital activity for rural development and planning worldwide. A physical suitability evaluation indicates the degree of suitability for land use, without respect to economic conditions. Since different crops need different physical conditions to grow, the main aim here is to find how much each crop yields given the climatic, edaphic and slope conditions. The model discussed in this paper considers not only the management views (practicality of raising and saving different crops) but also the interaction between different multiple interrelated factors. In addition, the suitability rating discussed in this paper is based on the FAO framework.