Erosive rainfall plays an extremely important role in forecasting and evaluating soil erosion by water.Erosive rainfall and rainfall erosivity (R) in Northern Jiangxi Province are studied based on data observed from 2001 to 2006.Results show that the rainfall amount standard and intensity standard of erosive rainfall events are 11.20 mm and 0.88 mm/h,respectively.The best equation for calculating rainfall erosivity factor in Northern Jiangxi is R=∑E.I₃₀.By calculation,the mean annual rainfall erosivity is 8695.43 J.mm/(m².h),maximum annual rainfall erosivity is 15140.64J.mm/(m².h),and minimum is 5601.10 J.mm/(m².h).The seasonal distribution of R value is mainly concentrated in summer.Through the simple algorithm of R proposed in the paper,percent change in annual rainfall erosivity is greater than percent change in total precipitation.