Abstract: According to the water and sediment of Xiaolangdi and Huayuankou hydrologic station，it calculates the sediment-transport water volume and total runoff volume proportional in lower Yellow River during different operational period，analyzes the law of sediment-transport and influence factors.The result presents that the sediment-transport water volume in lower Yellow River has better relationship with indexes of Xiaolangdi’s hydrologic data under the erosion and deposition state in flood season.In general，the sediment-transport water volume increase with the increment of runoff，flow and sediment；on the contrary，it decreases with increment of sediment concentration and incoming sediment coefficient.The ratio of the sediment-transport water volume to runoff gradually increases and has stable trend with increment of sediment concentration and incoming sediment coefficient.It indicates the sediment-transport water volume is small and stable，the efficiency of sediment-transport is more higher in flood season.After Xiaolangdi reservoir regulation of flow and sediment，it reached the optimized allocation purpose of water and sand resources in lower Yellow River channel.