The study of soil saturated hydraulic conductivity(Ks),one of the parameters describing soil water infiltration capacity,is very important for the soil infiltration process.Based on the analysis of Ksof soil under the main planted forests in the loess hilly region of Western Shanxi Province,the correlations between Ks and the physical properties and organic matter contents of soil was established using analysis of variation (ANOVA) and principal component analysis,the dominant factor affecting the Kswas figured out.The results showed that Kswas significantly higher in all forest types than the barren land and decreased negatively exponential with the increase of soil depths;The dominant factors affecting Kswere soil bulk density,capillary porosity,aggregate content larger than 0.25 mm,soil organic matter content and soil texture;Soil physical properties such as soil bulk density,capillary porosity could be improved by increase of soil organic matter content;Suitable mixed forest types with species such as Betula platyphylla Suk.and Larix gmelinii Rupr.chosen for afforestation were recommened.