THE USE OF GEOGRAPHIC INFORMATION SYSTEMS (GIS) AND REMOTE SENSING (RS) TO FACILITATE THE ESTIMATION OF RUNOFF FROM WATERSHED AND AGRICULTURAL FIELDS HAS GAINED INCREASING ATTENTION IN RECENT YEARS. THIS IS MAINLY DUE TO THE FACT THAT RAINFALL-RUNOFF MODELS INCLUDE BOTH SPATIAL AND GEOMORPHOLOGIC VARIATIONS. THE US DEPARTMENT OF AGRICULTURE, NATURAL RESOURCES CONSERVATION SERVICE CURVE NUMBER (USDA-NRCS-CN) METHOD WAS USED IN THIS STUDY FOR DETERMINING THE RUNOFF DEPTH. RUNOFF CURVE NUMBER WAS DETERMINED BASED ON THE FACTORS OF HYDROLOGIC SOIL GROUP, LAND USE AND HYDROLOGIC CONDITIONS. GIS AND RS WERE USED TO PROVIDE QUANTITATIVE MEASUREMENTS OF DRAINAGE BASIN MORPHOLOGY FOR INPUT INTO RUNOFF MODELS SO AS TO ESTIMATE RUNOFF RESPONSE. THE STUDY WAS CONDUCTED ON THE TANGE SHOUL SUB-BASIN OF THE DOROUDZAN DAM IN FARS PROVINCE. INCREASE OF WATER SURFACE (TANGE SHOUL RIVER) CAUSE TO FLOOD LARGE PARTS OF AGRICULTURAL FIELDS IN FLOODPLAINS THAT LEAD TO LOSS OF PROPERTY TO FARMERS. THE PROCESS OF DETERMINING SPATIALLY DISTRIBUTED RUNOFF CURVE NUMBERS FROM LANDSAT IMAGES IS PRESENTED IN THIS STUDY USING GIS AND IMAGE PROCESSING SOFTWARE. SPATIALLY DISTRIBUTED RUNOFF CURVE NUMBERS AND RUNOFF DEPTH WERE DETERMINED FOR THE WATERSHED FOR DIFFERENT LAND USE CLASSES. OUR DESTINATION IS INSPECTING OF THE EFFECT OF RUNOFF FROM EACH SUB-BASINS ON THE TANGE SHOUL RIVER FLOOD, THUS, SUB-BASINS PREFERRED IN ORDER TO PREVENT AGRICULTURAL FIELDS FROM DAMAGING.