Polyacrylamide (PAM) can enhance soil structural stability,however its influence on soil hydraulic conductivity is not very clear.Effects of PAM application rate and method on saturated hydraulic conductivity were studied in laboratory through a soil column leaching experiment.PAM was mixed with the soils (sodic and nonsodic soils),respectiviely,or spread over surface of the soils at a rate of 0,1/5 000,1/2 000,and 1/1 000 (PAM/dry soil in weight).The experimental results indicate that hydraulic conductivity of nonsodic soil was greater than that of sodic soil when no PAM was applied.PAM application through mixing obviously decreased steady hydraulic conductivity of the two soils,but its effect on sodic soil was greater than on nonsodic soil.PAM application through spreading decreased hydraulic conductivity of nonsodic soil.Steady hydraulic conductivity of sodic soil decreased with the increase in PAM application rate when the rate was low,but it increased when the rate was getting high.In order to maintain a great soil hydraulic conductivity,PAM application rate should be kept as lower as possible,or PAM is applied through mixing in nonsodic soil or through spreading on surface of sodic soil.