非饱和渗透系数为非饱和黄土分析中的关键参数，是基质吸力或体积含水率的函数，具体为何种函数关系尚难有定论，且非饱和渗透系数测定较为困难，运用土-水特征曲线间接推导具有较大随机性，稳态法及室内瞬态剖面法需考虑土体扰动影响。为此用原位瞬态剖面法处理黄土地区降雨入渗监测数据，得到黄土的非饱和渗透系数与体积含水率之间的关系，同时引入了田间测定非饱和渗透系数的 法，二者计算结果具有较高的吻合度，证明了 法的适用性。此外，基于不同时间体积含水率对深度的变化，提出用对数曲线拟合体积含水率与深度的关系，并应用到瞬态剖面法数据处理中，用此关系对 法的一个基本假定进行了修正，得到了更接近实际的结果。

Unsaturated hydraulic conductivity is a key parameter in unsaturated loess analysis, it is a function of matric suction or volumetric water content, but difficult to deternine which specific function relationship is. Moreover, the unsaturated hydraulic conductivity is difficult to measure, indirect deduction from soil water characteristic curve (SWCC) is more random, steady-state and indoor transient profile method require taking the soil disturbance into account. Under these circumstances, the in-situ transient profile method is adopted to process the natural rainfall infiltration monitoring data, the relationship between the unsaturated hydraulic conductivity and the volumetric water content of loess is obtained. In addition, based on the actual distribution of volumetric water content at different times, the relationship between the volumetric water content and depth is proposed by using a logarithmic curve, and applied to the data processing step of the transient profile method. The results of the in-situ transient profile method show that the relationship between the unsaturated hydraulic conductivity and the volumetric water content is an exponential function. Meanwhile, due to rapidly evaluating the unsaturated hydraulic conductivity in field, the method is introduced. The calculated results show that method has a high degree of agreement with in-situ transient profile method. On the other hand, the logarithmic curve is used to fit the relationship between the volumetric water content and depth when using the method; thus, one of the basic assumptions of the method is amended by the logarithmic curve relationship; and the results of the modified method are closer to the actual conditions.