Abstract: Soil and water conservation benefits method and hydrological method are adopted in the previous studies on effect of soil and water conservation on hydrological and water resources. Because of water resources with narrow sense as assessment basis both of them can not systematically bring to light the physical mechanism of effect of soil and water conservation on hydrological cycle, so that the research achievements can not really reveal the effect of soil and water conservation on hydrological and water resources. Distributed hydrological model based on physical mechanism taking narrow and broad sense water resources as assessment basis can overcome their serious shortcomings. The research progress of distributed hydrological model is reviewed. Using the distributed hydrological model based on physical mechanism (WEP-L), taking the key area of soil erosion control in the Yellow River basin, the area between Hekou and Longmen towns as a case, the effect of soil and water conservation on hydrological and water resources is quantitatively studied. The research results indicated that soil and water conservation enables absolute and relative amount of broad sense water resources increase by 7.26 billion m and 27.1 % respectively, and makes absolute and relative amount of narrow sense water resources to decrease by 0.90 billion m and 14.4% respectively. Soil and water conservation changes the composition of narrow sense water resources, that is amount of surface water resources decreased, amount of unrepeated water resources and water ground water resources increased.