Abstract: Resent advances in remote sensing, geographic information systems, and computer technology make the use of distributed hydrological model, based on digital elevation model (DEM), an attractive approach or tool to studying hydrological processes and evolution laws of water resources under changing environment. But distributed hydrological model is not perfect compared with lumped hydrological model. In order to promote its development, based on DEM, this paper discusses and sums up the characteristics of distributed hydrological model, then probes into two main ways and means of constructing distributed hydrological model. One way is like SHE model, another is like SWAT model. Although distributed hydrological models can be made in different ways, the primary structure of the model is quite similar. A typical structure of DEM based distributed hydrological model is provided in this paper. To better study the impact of the changing environment on hydrological processes, a watershed must be divided into subunits. This paper expressly discusses the three most common techniques used to discretize a watershed, which are respectively grid cell discretization, representative hillslope discretization and subwatershed discretization. In the final, as to the problem of constructing model, the methods of building the components of the distributed hydrological model is set forth from three aspects: input module, unit hydrology model and river routing model. A brief comment on the current distributed hydrological model research and some advice are given in the conclusion. All these will provide a guidance for making distributed hydrological model based on DEM.

Key words: digital elevation model, distributed hydrological model, river routing model, unit hydrology model, watershed discretization