In order to analyze the bed load movement characteristics in the confluence area under the Taoyuan junction,the fixed bed flow and sediment transport experiments were carried out by using the integral fixed bed physical model to observe the distribution of water flow elements and sand transport belts under different flow rates.It is found that the hydrodynamic conditions in the confluence area are complex and changeable with the different confluence ratio,however,the range of sediment deposition in the confluence area is always closely related to the distribution of the main flow area.The bed load sediment is transported along the main stream,and the sedimentation bodies are mostly found at the boundary line of the transport belt,the turning point of the streamline and the concave under the local back surface of the riverbed.In the middle and low water period,the sediment transport under the dam is short distance because the discharge flow velocity is large and the flow velocity decreases rapidly along the river.In the flood period,the sediment transport is long distance because the river velocity is large.