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为明确黄河河口段河长与水沙过程的响应关系,采用实测资料分析及理论探讨方法,分析了1954～2012年间不同行河时期黄河河口段的水沙变化(利津站)及河长变化.研究表明:1954～2002年水沙呈下降趋势,2002年后因小浪底调水调沙作用,2002～2007年水沙量较1996～2002年略有回升,随后呈继续减小趋势;河口段河长随改道骤减,随后以先快后慢的速率不断增长,增长速率近年受人类活动影响显著.在考虑累计来沙量单一因素的基础上,引入年均来沙系数,综合考虑水沙条件,建立了分时期(不同流路或汊道)及半统一的黄河河口段河长经验计算公式,计算效果较好,可适用于不同条件下河口段河长的计算及预测.“,”In order to determine the relationships between the length of estuarine reach and the flow and sediment regime,the methods of the field data analyses were used in this study.The changes in flow and sediment conditions at Lijin and the length of estuarine reach were analysed during 1954-2012,and it is discovered that there was a decrease in water volume and sediment load during 1954-2002,but after 2002 the water volume and sediment load increased relatively owing to the operation of Xiaolangdi Reservoir.In addition,every time after channel avulsion at the Yellow River estuary,the river length downstream of the diversion point was suddenly shortened and then it increased with a decreasing rate;moreover,the rate of increasing was reduced evidently caused by the effects of human activity in recent years.Different empirical formulas for the length of estuarine reach of the Yellow River were established by taking different factors (single factor:cumulative sediment amount,incoming sediment coefficient) into account during different periods and the whole period.The proposed formulas are simple in form and the calculated data agreed generally with the measured data;therefore these formulas are applicable to the calculation and prediction of the length of estuarine reach,so as to provide references for studying the channel evolutions of the Yellow River estuary.