Taking the artificial forest land of Pinus sylvestris var. mongolica of different ages in Minqin National Study Station on Desert Steppe Ecosystem as the object, the soil physicochemical properties of P. sylvestris var. mongolica of different ages were measured, and the nutrient status of P. sylvestris var. mongolica forests were compared and analyzed. The results are as follows. (1) The vertical change of soil water content of different forest ages is not significant, and the soil water content changes significantly in the same soil layer of different forest ages. The surface soil water content of the middle-aged forest is the lowest of 4.34%, and the water content of the 40-50 cm soil layer of the near-mature forest is the highest of 17.21%, significantly higher than that of other forest ages (P<0.05). (2) There are significant differences in soil pH and electric conductivity in the P. sylvestris var. mongolica plantations of different ages. The pH of the middle-aged forest is the lowest at different soil depths. The soil pH in different soil layers of each forest age group is greater than 8, showing weak alkalinity. The soil electric conductivity is in the order of middle-aged forest> young-aged forest> near-mature forest, and the soil electric conductivity of the middle-aged forest is significantly higher than that of the young forest, showing a decreasing-rising trend with the increase of the soil depth. (3) The forest age has a significant effect on the soil nutrients of P. sylvestris var. mongolica plantations. The content of total nitrogen, organic matter, NH₃-N (ammonia nitrogen), available phosphorus and effective phosphorus in the middle-aged forest are higher than those of other forest ages, and the difference is significant (P<0.05). (4) Principal component analysis of soil fertility of different forest ages shows that the total soil nitrogen, organic matter, available phosphorus, NO₂-N (nitrous nitrogen) and NH₃-N are in the first three main components.