Abstract: Soil saturated hydraulic conductivity (K_s) is one of the most important hydraulic parameters, and its determination in the laboratory has been shown to be influenced largely by column size. This study estimates measurements of K_s in the lab using six different column sizes: 5, 10, 15, 18, 23 and 29.5 cm. Constant water head method was used, and disturbed Lou soil, a typical clay loam soil in Guanzhong region, was selected. Results showed that K_s decreased over time, and the range of descending changed greater at the initial stage than later. At the column size range of 5 -30 cm, K_s decreased with increasing column size. A linear regression analysis of two data sets of K_s and column size showed that the K_s data were linearly correlated with the size data following y =0.000 4x +0.003 7(R² =0.965 1). This study may serve as reference to choose reasonable time and size in measuring the K_s of disturbed soils.