Abstract: It is one of the important contents in the topography analysis as well as in the hydrological distribution models that how to determine flow directions of water in each cell of DEM.Although many hydrologists have already put forward a lot of different flow direction algorithms over the past dozens of years.A new approach of assigning flow directions of DEM cell is proposed in this study, which is called local topography-based variable flow width method.This approach is based on the analysis of the local topography formation defined within a 3?3 cell window with the recognition that the flow distribution coefficient for each flow direction is changeable with the corresponding slope and outflow width.In the paper, this method has been tested on the digital topography of an actual watershed.Two indices, the total catchment area (TCA) and specific catchment area (SCA), produced by four flow routing algorithms including the D8 (eight flow directions), Dinf (an infinite number of possible single flow directions), MS (multiple flow directions based on slope) and the local topography-based variable flow width method, are selected to compare and analyze efficiencies of those four algorithms.The result shows that the local topography-based variable flow width method can obtain more reasonable spatial distribution of water accumulation, compared with the D8, Dinf, and MS.