流域地形是决定水系生成的一个关键性因素，是数字流域和分布式水文模型研究的主要内容。针对现有应用数字高程模型进行水文分析时存在的若干问题，在对当前数字高程模型的生成算法进行讨论的基础上，提出在利用现有方法进行内插的过程中加入河流数据进行方向判断和高程修正的算法。通过试验与分析，得出应用本方法生成的数字高程模型在保留精度的基础上，较好地反映了地表水文特征和河流结构，利用它不仅可以进行一般的地学分析，还能够作为水文模拟与研究的数据源。

The watershed topography is a key factor for extraction of the drainage,and it is also a very important topic in the study of digital watershed and the distributed hydrological models.The paper firstly discusses some problems in hydrological analysis by applying the DEM,and describes three kinds of interpolation models to produce the DEM.Then the author introduces an interpolation method which could improve the accuracy of the DEM by judging the stream's flow direction.Finally the interpolation algorithm is applied to generate the DEM by using the elevation and stream data in the area of southwest China.We analyze the results of the experiment,and find that the DEM created by this method not only keeps its precision but also presents a fine surface runoff character and stream pattern.Moreover,by comparing with the stream lines that extracted from different DEMs,the paper concludes that the DEM created by the hydrological improved algorithm is more useful in dealing with the hydrological analysis.