Abstract: The study is to study the changes of soil quality and the relationship with soil erosion during degradation/restoration in sloping-land with purple soils in Hengyang. By the method of spatiotemporal substitution, dynamics of soil water stable aggregation and soil organic carbon (SOC) in land degradation/restoration process in typical area was studied. The results showed that: (1) the number of ＞0.25 mm water stable aggregation tended to decrease in the process of soil degradation, while during restoration, the number of ＞0.25 mm water stable aggregation tended to increase; (2) SOC was decreasing/increasing in the process of land degradation/restoration; (3) The relationship between ＞0.25 mm water stable aggregation and SOC match the equality: y=22.321x+3.541 (R2=0.932); (4) The relationship between mean weight diameter (MWD) of soil water stable aggregate with restoration years and ＞0.25 mm water stable aggregation matched the equality: y=1.984e-0.126x (R2=0.875) and y=0.098x+0.123 (R2=0.981) respectively.