摘要：基于数字高程模型，本文利用ArcGIS9.3的水文分析模块，根据不同的集水面积阈值, 提取了重庆长江流域河网信息，通过网格法计算了相应的水系分维。根据集水面积阈值与水系分维的相互关系, 确定该流域水系分维值为1. 036，经计算得到的河网特征以及流域信息与实际河流水系特征及流域信息基本吻合。

Abstract：Based on DEM, the information of river networks of Long River Basin in Chongqing is extracted, according to the different catchment threshold values and using the hydrologic model by ArcGIS9.3. the fractal dimension of the river network is calculated by the grid method. Based on the relationship between different catchment threshold values and fractal dimension of Long basin, fractal dimension value of Long basin is 1.036, The channel network extraction from DEM w as basically consistent with the factual river system.