The purpose of this study is to develop a GIS application and interface model (GISCELWAB) for the temporal and spatial simulation of surface runoff from a small watershed. The model was constituted by three sub - models : The input data extraction model (GISINDATA) which prepares cell-based input data automatically for a given watershed, the cell water balance model(CELWAB) which calculates the water balance for a cell and simulates surface runoff of watershed simultaneously by the interaction of cells, and the output data management model(GISOUTDISP) which visualize the results of temporal and spatial variation of surface runoff. The input data extraction model was developed to solve the time-consuming problems for