Abstract: A fractal method is employed to estimate soil hydraulic conductivity from the particle-size distribution data(PSD) in the paper.The pore surface fractal dimension is first determined using the PSD curve,and then used in the fractal conductivity models of Mualem and Burdine to predict the field conductivity function.Compared with hydraulic conductivity obtained from the laboratory water retention curve using the statistical pore-size distribution models,the PSD based fractal method produces much better results for 217 samples from the UNSODA soil hydraulic database.