Abstract: We extracted the digital river network from the digital elevation model (DEM) data of the Qujiang River basin, so the basin boundary was delineated, and the topographic index distribution of this region was calculated. The DEM-based Distributed Rainfall-runoff Model (DDRM) was applied to simulate the rainfall-runoff processes in the study region. The performance of the DDRM on the simulation of rainfall-runoff processes in the Qujiang river basin was evaluated by using three indices, i.e., Nash-Sutcliffe efficiency coefficient, relative errors of both flood peak discharge and flood peak time. Meanwhile, we also compared the performance of DDRM under two DEM grid resolutions (1km and 2km). Results show that the DDRM based on both 1km- and 2km- resolution DEM performs well in the simulation of rainfall-runoff in the Qujiang River basin, and the simulation accuracy based on the 1km grid is slightly better than the 2km grid. Because the DDRM has the simple structure, less parameters, concise description on physical process as well as the ability to simulate the spatial distribution of soil moisture and runoff amount, it can be used for hydrological simulation in ungauged basins.