Abstract: The value of R, erosive force of rainfall,is one of the basic factors used for setting up soil loss equation.Through analysing the data of soil erosion and erosive rainfall measured on the standard runoff pot,the best index in the northeast mountain region of Yunnan Province for calculating the erosive force of rainfall is defined as: R=E₆₀·I₃₀. According to this index and the data of rainfall from 16 stations in 1980-1997,we calculate the erosive force of rainffall (R) of every station in the northeast mountain region of Yunnan Province, and analyse the time space distribution characteristics of erosive force of rainfall in this region.The results of the calculation and the analysis show that the average annual value of R in this region is 293.8J/m².For the distribution in a year,the value of R is higher in June～August,equivalent to 77.68% of the annual value.The annual variation of the value of R is also very large with a maximum of R 726.5J/m² in a year to a minimum of R 94.2J/m² in a year. For the spatial distribution,the value of R in northern area was higher than that in southern area,and in the dry and hot valley of the Jinsha River is lower than that in high altitude mountain zone.