利用双套环法对长江中上游水土流失严重区的50个县（市）进行原位测试，对其典型土壤的稳渗速率及其影响因素进行了分析研究。结果表明：土壤稳渗速率在长江中上游地区呈现规律性的地域分异, 四川盆地以及毕节地区是稳渗速率高值区，陕南和陇南地区、三峡库区以及丹江口库区是稳渗速率一般区，金沙江下游地区以及湘东赣南红壤丘陵区是稳渗速率低值区；土壤稳渗速率随土类发生有规律变化，黄壤系列土类最大，然后是石灰土、紫色土，红壤系列土类稳渗速率最小；土壤稳渗速率与质量密度呈负相关关系，与孔隙度、大于0.25 mm风干土水稳性团粒含量、有机质含量以及粉/粘呈正相关关系。

The field tests on stable infiltration rates of typical soil and their affecting factors conducted in the 50 counties and cities, which belong to the severe soil-water losing region of upstream and midstream areas of Changjiang River were studied by the doubl-ring method. The results show that steady infiltration rate varies regularly in different regions and in different soil types. Sichuan basin and Bijie area are the high-value regions of stable infiltration rate; South Shanxi Province, South Gansu Province, Three Gorges Reservoir-area and Danjiang Reservoir-area represent mid-value regions; The downstream area of Jinshajiang River and the red-earth rolling terrains of East Human Province and south Jiangxi Province belong to Low-value area. The infiltration rate Changes with soil types, ranged from high to low in order of yellow soil, lime soil, purple soil and red soid; the change of it with soil bulk density presents a negative correlation, but the relations between it and porosity, water-stability aggregate magnitude of air dry soil(diameter over 0.25 mm), organic content and ratio of silt to clay, respectively, are positive ones.