本文研究了九龙江河口湾的泥沙运动特点与沉积动力机制。结果表 明：（１）泥沙主要来源于河流输沙和潮流输沙；潮流输沙量明显大于河流输沙量；涨潮 输沙量通常大于落潮输沙量；潮流输沙在枯水期尤为显著，而河流输沙则集中在洪水 期。（２）底沙推移运动主要发生在水道床面，系局部冲刷所致；推移质输沙表现为沙洲 推移，沙嘴延伸或水下沙体游移；研究发现，在涨潮流占优势的鸡屿北水道有反向（向 西）推移质输沙的迹象。（３）自６０年代以来，九龙江河口上方各河道相继建闸截水，加 强了河口湾潮流势力，使得悬移质泥沙运动呈现较强的规律性，即具有洪出枯进、上 出下进和南出北进的明显趋势，以致在湾内新形成两对较大泥质淤积区。 This paper studies the characteristics of sediment movement and depositional dynamics in the estuary of Jiulong River. The results show that: (1) Sediment mainly comes from river sediment transport and tidal current sediment transport; tidal current sediment discharge is obviously larger than river sediment discharge; tidal discharge sediment discharge is usually larger than ebb tide sediment discharge; tidal current sediment transport is especially significant in dry season River sediment transport is concentrated in the flood period. (2) The movement of sediment mainly occurred in the channel of watercourse, which was caused by local scouring. The transgressive sediment transport showed the sandbar migration, the extension of sand nozzle or the drift of sand body. The study found that in the Jiliu North Channel There is reverse (westward) signs of sediment transport. (3) Since the 1960s, sluice gates have been built in all river courses above the mouth of the Jiulong River estuary, strengthening the tide forces in the estuary so that the suspended sediment movement shows a strong regularity, Ascending and descending the obvious trend of northward advancement resulted in the formation of two new pairs of larger muddy siltation areas within the bay.