对三峡水库运行前（1983-2002年）后（2003-2005年）中华鲟产卵场产卵季节（10-11月）的水文状况进行了比较分析，并根据所建立的水文要素适合度模型，对三峡水库运行前（1983-1986，2002年）后（2003-2005年）8个年份产卵季节水文状况对于中华鲟产卵的适合度进行了分析。结果表明：2003年三峡水库蓄水以来中华鲟产卵场产卵季节的水文状况发生了显著变化，产卵季节平均水温上升了 1.48 ℃ （ 8.2% ），含沙量降低了 0.36 kg/m3（ 91.8% ）。平均适合度模型的分析结果表明，虽然整个产卵季节水文状况对于产卵的综合适合度呈现出先上升后下降的趋势，但整个产卵季节水文状况的适合度都比较高，并且中华鲟的产卵活动并不总是发生在水文状况适合度最佳（即综合适合度波峰值）的时候，说明水文状况并不是决定自然繁殖发生时间的唯一因素。产卵前含沙量的变动趋势由水库运行前的稳中下降转变为运行后的稳中上升，说明含沙量的剧烈下降可能对中华鲟的自然繁殖活动不利。中华鲟自然繁殖发生时间应是多种因素综合作用的结果，除水文状况外，科研捕捞活动、年度之间自然繁殖群体的生物学差异等都可能对自然繁殖活动发生的具体时间产生影响。

In the spawning area of Acipenser sinensis of downstream waters of the Gezhouba Dam, the hydrological conditions in spawning seasons (October-November) before (from 1983 to 2002) and after (from 2003 to 2005) the operation of the Three Gorges Project (TGP) were analyzed. It showed that the hydrological conditions during the spawning seasons were changed obviously since the operation of Three Gorges Reservoir (TGR) in the year of 2003, and that average water temperature in the spawning season was increased by 1.48℃ ( 8.2% ), and the sediment content was decreased by 0.36 kg/m3 ( 91.8% ). A suitability model based on hydrological conditions was proposed to evaluate the suitability of daily hydrological condition for spawning during the spawning seasons before (from 1983 to 1986) and after (from 2003 to 2005)the operation of the TGP. The average suitability model showed that spawning suitability for spawning increased at first and then decreased in the whole spawning season. However, the spawning suitability was comparatively high in the whole spawning season. The spawning activities of Acipenser sinensis don’t always take place in the best situation time, i.e. the suitability of hydrological condition is the highest. That is to say, the hydrological condition is not the only factor to determine the spawning time. The variation trend of sediment content before spawning used to decrease in steady before the TGP operation, however, the trend increased in steady after the reservoir operation. It means that the sharply decrease of silt content may bring on adverse effects on the natural reproduction of A. sinensis. In overview, the occurrence time of natural spawning activities of A. sinensis should be the integrated results of hydrological conditions, scientific-study capturing activities, differences of spawning cohorts and some other possible factors