[Objective] In order to improve the accuracy of saturated hydraulic conductivity in the Mualem model. [Methods] The modification of the saturated hydraulic conductivity k_s in the Mualem model was studied by theoretical method combined with data statistics. Based on the Brooks-Corey soil-water characteristic curve(SWCC) of unsaturated soil, a theoretical relationship between modified hydraulic conductivity and SWCC was presented, in which the correlation parameter was solved by regression analysis. [Results] Experimental data of undisturbed loess were used to evaluate the prediction outcomes of the Mualem model considering modified hydraulic conductivity k_o, which showed satisfactory result. [Conclusion] This theoretical model can be used to determine unsaturated hydraulic conductivity directly from SWCC, which possesses some references for further research on the prediction of unsaturated hydraulic conductivity.