In this study, the characteristics of erosion runoff and sediment was analyzed, as well as the evolution of soil erodibility, in naturally restored woodland and bare land plots using 40 years of monitoring data from the Ecological Experimental Station of Red Soil, located in Jinxian County, Jiangxi Province, South China. The results showed: 1) Both woodland and bare land soils exhibited an increase in sand content and a decrease in clay content over time, while organic matter content significantly increased, with woodland showing higher accumulation rates. 2) Runoff patterns differed significantly—bare land exhibited rainfall-dependent fluctuations, whereas woodland runoff declined steadily, decreasing to approximately 58% of its original level. following shrub-grass establishment between 1993 and 1996. 3) Sediment yield correlated with runoff trends. Bare land’s sediment peak preceded the runoff maximum, indicating a transition in erosion resistance during 1994-1995, while woodland sediment approached zero after 1996. 4) The K factor for bare land initially increased, then declined with organic matter accumulation, whereas the K-factor for woodland showed the opposite trend due to progressive clay loss. In conclusion, long-term vegetation restoration effectively controls runoff and sediment yields, while bare land remains erosion-prone despite slight improvements.