The purpose of this study is to develop a conceptual model to analyze the sediment delivery ratios and sediment yield in watershed.The key concept of the model is to divide watershed into numerous grids and use the maximum slope method to establish the migration paths of sediment based on physiographic parameters. Then, a landside model is used to estimate the sediment inflow (neglect surface erosion). In conjunction with the model of the sediment delivery ratio of slope constructed by following the linear reservoir concept, the movement of sediment and the sediment yield in watershed can be first was examined analysed. This conceptual model was tested on the basis of hypothetically designed cases to examine its reliabitity. The conceptual model was then applied to Shihmen Reservoir watershed during Typhoon Aere to estimate the sediment delivery ratio of the watershed , the sediment yield of the control point (sediment hydrograph), and the distribution of the diameter of sediment particles.