In order to study the impact of different land preparation measures on the quality of the soil of the terraced orchards, three typical slopes (optimized prepared slope T_y, traditional prepared terraced slop T_c, and abandoned land CK) in navel orange orchard development demonstration area of Xiaoyang small watershed in Ningdu County, southern Jiangxi Province were selected as the research object. The primary component analysis method (PCA) was used to screen the minimum data set indicator to evaluate the soil quality in this area. The results showed that: (1) Total Data Set(TDS) and Minimum Data Setting(MDS) soil quality indexes had a significant positive correlation, R² = 0.604, indicating that MDS could instead of TDS to conduct soil quality evaluation of navel orange orchard development demonstration area in Ningdu County; (2) The soil quality index (SQI) of 3 typical slopes was manifested as: optimizing prepared terraced slope(0.477) > abandoned land(0.436) > traditional prepared terraced slop(0.220). There was no significant difference between T_y and CK, and SQI of T_y was about 1.16 times higher than that of T_c, indicating that soil quality would be significantly improved under optimized soil preparation measures; (3) In general, the SQI of the surface layer (0—10 cm) was higher than that of the deep soil (10—20 cm) in the different soil layers of the orchard. The SQI classification showed that the soil quality of the optimized terraced and abandoned land was better than that of the traditional prepared terraced slop. The research results can provide a scientific basis for the utilization and management of slope land resources in the red soil hilly region of South China and the layout of soil and water conservation measures after terrace construction.