The conservation of forest soil can significantly affect soil erosion and ecological security. In this study, rainfall erosivity was optimized on the basis of the rainfall characteristics of different climatic zones. The soil conservation capability of forest ecosystems was quantitatively estimated using the revised universal soil loss equation, which is based on long-term observational data of the Chinese Ecosystem Research Network, and both spatial and temporal variations were analyzed. ① The simulation results of the daily rainfall erosion model in tropical regions with high rainfall were better than those in subtropical and temperate regions. After parameter optimization, the simulation effect of the subtropical and temperate regions was significantly improved. ② From 2005 to 2015, the amount of soil conservation by forest ecosystems ranged from 4.44 to 891.67 t hm^-2 a^-1. The soil conservation capability exhibited a significant spatial pattern, with an increasing trend from north to south (R²=0.65^***), and the soil erosion rates were all greater than 97%. ③ Precipitation exhibited a significant positive correlation with soil conservation (R²=0.52^*), and both normalized difference vegetation index (NDVI) and soil texture exhibited strong correlations with realistic erosion (R²=0.64^**, R²=0.41^*). There was a power function relationship between vegetation age and the rate of change of soil conservation.