Abstract: 【Objective】 To evaluate the soil microbial ecology of walnut in different planting years in southern Xinjiang with a view to provided reference for the analysis of soil degradation and soil microbial ecological health in walnut orchard. 【Method】 Using the method of space-time substitution, walnut trees in Yecheng area were selected as the research object, the changes of soil physical and chemical properties, microbial quantities and soil enzyme activities in time (5,8-10,15,20-25 planting years) and space (at different soil depths) were analyzed, and the principal component-cluster analysis was used for evaluation. 【Result】 With the extension of the planting years of walnut, pH of 0-20 cm and 20-40 cm soils showed an overall acidification trend. The contents of total salt and other nutrients except available phosphorus showed obvious trend of surface accumulation, and the contents of total nitrogen and organic matter decreased at first and then increased. The number of soil cultural bacteria, actinomycetes and fungi also showed trend of surface accumulation. With the extension of planting years of walnut, the number of soil bacteria increased first and then decreased, and the numbers of actinomycetes and fungi increased. The activities of soil urease and sucrase decreased with the increase of soil depth, but there was no obvious change rule with different planting years. Principal component-cluster analysis showed that the comprehensive score of 0-20 cm soil microbial ecology ranked as walnut planting for 15 years > 20-25 years > 8-10 years > 5 years. The comprehensive score of 20-40 cm soil microbial ecology ranked as walnut planting for 20-25 years > 8-10 years > 15 years > 5 years. 【Conclusion】 The microbial ecological conditions of walnut planted in 5 years were the worst. The soil microbial ecological conditions were the best for 15 years of 0-20 cm surface soil and 20-40 cm subsurface soil.