In 18 years old

22 years old and 38 years old Larix-principis-rupprechtii plantations in Saihanba Forestry Station of Hebei Province

soil quality indicators such as physicochemical properties

enzymatic activities and microbe quantity were researched comprehensively.The key indexes and varying patterns of soil quality were understood by data analyzing.Soil indicators have significant differences in even-aged stands.With the increasing of soil depth

the soil bulk density and pH values magnify correspondingly

while the values of the other 12 indicators(including soil water content

capillary water holding capacity

capillary porosity and so on) have an adverse trend.The same indicator among uneven aged stands also has significant difference.The optimal indicators in 18 years old stands are the catalase activity and bacteria quantity

while SWC

capillary water holding capacity

capillary porosity

organic matter(OM)

urease activity and fungi in 22 years old stands

and soil bulk density

total K

rapidly-available phosphorus

total nitrogen and actino-mycetes in 38 years old.The results of principal components analysis(PCA) showed that the soil bulk density

capillary water holding capacity

capillary porosity

quantities of OM

actinomycetes and fungi are optimal indicators of soil quality.The comprehensive score of Larix-principis-rupprechtii soils in 18

22 and 38 years old plantations are 0.122

0.253 and.375

respectively.The highest score of soil quality in 22 years old stands suggests that the soil is the best.