Abstract: Based on the SuperMap GIS, an agricultural land suitability assessment system(ALSAS) for Zhangzhou Area in Fujian Province was developed using the vector data model and the intersecting result of evaluation factors as the evaluating unit. The selection of evaluation crop and evaluation factors, determination of target gradation and weights can all be done by the user. The user can exclude the land area that do not include in the evaluating area. The system makes itself more convenient by storing the crop ecological index database in practice. It can deal with all kinds of data timely, and has other functions related to crop assessment such as analysis and statistics. It can serve as a guideline for introducing new kind of crop and agriculture structure adjustment. From the practice of developing the ALSAS，its implementation process and methods based on GIS were discussed.