Abstract:Constant head method was used to measure saturated hydraulic conductivity(Ks)of 26 soil profiles between 100 to 1000 m above sea level．The relationship between Ks and soil texture and．Soil bulk density， the regulation that Ks changes with soil depth，the difference of Ks between undisturbed and disturbed soil were analysed in this article．It was also pointed out in this article that the range of Ks in Beijing Xishan is between 1.3·10-2cm／min and 14.9·10-2cm／min；the value of Ks drops from 6.5·10-2 cm／min to 3.7·10-2cm／min with the depth increasing；the value of Ks goes down with the increasment of content of clay particle；the value of Ks in undisturebed is two time larger than that of disturbed soil， but they were in the same quantify degree．