Long-term sub-soiling tillage improves soil structure and physical properties by increasing soil pores and porosity, enhancing water retention, and boosting crop productivity. The study compared sub-soiling tillage at 30 cm depth to conventional tillage at 15 cm depth over 8 years in an arid region of China. Results showed that sub-soiling increased soil porosity, organic carbon content, moisture capacity, and hydraulic conductivity while decreasing soil bulk density. These improvements were more significant under sub-soiling than conventional tillage, indicating that sub-soiling is an effective method for enhancing soil quality and preventing degradation.