Abstract: On the basis of the characteristics of the porous and fissure water flow in the karst watershed, a mixed runoff routing method integrating interactions of the Darcy flow, fissure flow and channel storage routing, is developed and used to improve the Distributed Hydrology-Soil-Vegetation Model (DHSVM). The improved model is applied in a small watershed of Chenqi with in the Puding Karst Ecohydrological Observation Station, Guizhou province. The model is calibrated and validated based on the observation data of the stream flow, the vegetation interception, the evapotranspiration and the soil moisture. The results show that this improved DHSVM is able to simulate the observed hydrograph with sharply raised and recessed flow characteristics, as well as evapotranspiration and soil moisture. The improved DHSVM is also able to simulate soil moisture content and evapotranspiration as well as their interactions with precipitation,karst fracture and vegetation cover. This study is very useful for analyzing the eco-hydrological processes and the eco-environmental effects with the changing land cover and land use in the Karst region Southern China.