DEM data of Chongqing Wanzhou District from four maps of 1:10.000 scale and 5m surface resolution are used to extract watershed network by D8 algorithm through HydrologyTools module in ArcGIS and according to surface runoff model principle and to calculate confluence acumulation amount in order to ultimately create a river network.The results show that it is relatively reasonable to set 50,000 grids as minimal flow accumulation water area threshold value for water system extraction of 1:10,000 DEM and that the accuracy of extracting efficiency and results by applying ArcGIS Hydrology module to extracting river network is feasible for mountainous area and based on 1:10,000 DEA data.