With the development of geographic information technology，it is necessary to simulate regional hydrological distribution and informational extraction by GIS.Based on the DEM basic data，the hydrological analysis tool of ArcGIS software was used to extract the hydrological information such as flow direction，flow accumulation，river network and basin area.And the selection of extraction threshold of river network was analyzed.The results show that with the increase of the threshold of the river network，the density of the river network is gradually reduced，and they have a power relationship；when the threshold of the river network is 2000，the length，drainage area，and spatial distribution of the extracted river network are related to the actual situation within the county；when the river network threshold is greater than 4000，the variation of the density and spatial distribution of the river network tends to be stable，and the extracted river network can be used for macroscopic planning and control.This study provides a reference for the extraction of river network water.