Abstract: Abstract:Using the model of Arc GIS program and the hydroloyical databases for 1981 to 2001,we analyze the landscape pattern and hydrological features of Dayekou river catchment(DYK)and Haichaoba river catchment(HCB)which are located at the Qilian mountains in northwest China. The results show that grassland and Picea crassifolia forest in DYK are the main landscape elements,and more important work in eco-hydrological process,while shrubs and bare land in HCB are the main landscape elements and of importance in eco-hydrological process. In DYK,the evapotranspiration is 61% of the rainfall,and the runoff coefficient is 0.39% whereas in HCB,the evapotranspiration is of the rainfall 41%,and the runoff is 0.59%. The coefficient study indicates that different forest landscape pattern will bring on different eco-hydrological effects in the arid mountain areas.