By setting up erosion simulation plots, the change characteristics of soil nutrients in the process of quality degradation of the cultivated layer of purple soil sloping farmland were studied. In this paper, taking purple soil slope cultivated land in the Three Gorges Reservoir area as the research object, five erosion degrees (0, 5, 10, 15 and 20 cm) and two management measures (no fertilization (CK) and conventional tillage (F)) in situ experiments, using field in situ detection, soil chemical property analysis and other means were used to study the restoration effect of conventional tillage on soil nutrients in eroded topsoil and the interannual variation trend of soil nutrients. The results showed that: (1) All indicators of soil nutrients in the topsoil showed that F>CK, indicating that F was better than CK in improving soil nutrients, and it had a better effect on soil nutrients. The improvement effect of organic matter, total nitrogen and available phosphorus was obvious. (2) The soil nutrients of the arable layer of the purple soil slope farmland were mainly enriched in the topsoil layer of 0—20 cm. The soil nutrient content in the 30 cm soil layer increased significantly, and the effect on the increase of the organic matter content in the 10—20 cm soil layer was the best. (3) After a continuous 4 years positioning test, the organic matter, total potassium, alkali-hydrolyzed nitrogen, available phosphorus, and available potassium increased by 4.33%~15.89% under CK compared with the background value, the total nitrogen content did not change significantly compared with the background value, and the total phosphorus content decreased by 11.78% compared with the background value; the F soil nutrient increased by 4.51%~49.46% compared with the background value. The results provide basic parameters for the regulation of the plough layer and the improvement of land productivity.