This paper aims to study the changes of soil chemical properties and hydrolase activity of Chinese fir plantation after close-to-natural transformation of Phoebe bournei and Machilus pauhoi after thinning of Chinese fir. Three kinds of stands were set up in Shanshan Forest Farm in Xinyu City, Jiangxi Province, which were Cunninghamia lanceolata pure forest (CLP), mixed forest of Cunninghamia lanceolata and Phoebe bournei (MPC), and mixed forest of Cunninghamia lanceolata and Machilus pauhoi (MMC). The chemical properties and hydrolase activities of 0-20, 20-40, and 40-60 cm soils were determined, and the relationship between soil chemical properties and hydrolase was analyzed. The results showed that soil organic matter, available phosphorus and available potassium in different stands decreased with the increase of soil depth. In the 0-20 cm soil layer, the pH, organic matter and available phosphorus of the reformed forest increased significantly, among which the organic matter increased by 22.52% and 21.04%, respectively, and the available phosphorus increased by 5.9% and 9.57%, respectively. In the 20-40 cm soil layer, the organic matter of the close-to-nature transformation forests increased significantly, and there was no significant difference in the available phosphorus and available potassium. The different stands had different effects on total nutrient. In the 40-60 cm soil layer, the contents of organic matter, total nitrogen, total potassium and available potassium were significantly different between the close-to-nature transformed forest and the pure forest of Cunninghamia lanceolata. Soil N:P in different stands was lower than that in the subtropics of China, and the available P element was lacking. Soil C:N and C:P in modified forest were higher than those in pure Chinese fir forest. The enzyme activities of cellobiose hydrolase (CBH), leucine aminopeptidase (LAP) and acid phosphatase (ACP) in soil of mixed forest of Cunninghamia lanceolata and Machilus pauhoi were significantly decreased compared with those of pure forest of Cunninghamia lanceolata. β-1, 4-n-acetylglucosaminoglycosidase (NAG), ACP, and the close-to-natural transformation forest of Cunninghamia lanceolata and wood shaplanus were significantly increased compared with pure forest of Cunninghamia lanceolata. The correlation analysis showed that soil pH, organic matter, total nitrogen, total phosphorus, total potassium, available phosphorus and soil enzyme activity were significantly correlated in different stands. [Conclusion] The close-to-nature transformation forest of the Cunninghamia lanceolata after cutting in pure interstand is helpful to the accumulation of soil nutrients, improves the soil quality of Chinese fir plantation, increases the diameter at breast height (DBH) and volume of Cunninghamia lanceolata, and alleviate the problems of soil fertility decline caused by single tree planting.