This study aims at analyzing the complex responses between sediment movement and flood based on a series of field investigations in Hekou)Tong guan section of the Yellow River.Results show that the channel adjustments such as sediment deposition and erosion vary with the difference of storm distribution pattern./Bed-exposed erosion,sand bar,and density flow are the causes for the abnormal phenomena of floods./Bed-exposed erosion may cut down the ability of flood peak reduction;and sand bar may impound a part of flood and then be broken.As a result,they may cause flood increasing abnormally.Density flow and coalmay make floods more complex.