Based on daily rainfall data of nearly 40 years over 32 meteorological stations in Heilongjiang Province, half-month rainfall erosivity was calculated, and basic database was built for GIS. The Kriging interpolation algorithm was used to analyze the spatial distribution variation of half-month rainfall erosivity and the trend analysis method was used to analyze their temporal dynamics.The results showed that:(1) The average half-month rainfall erosivity of each meteorological station from the second half of April to the first half of October presented a single-peak curve which increased gradually at first, and reached the maximum value in July and August, then descended gradually.(2) The half-month rainfall erosivity exhibited great spatial differences especially in July and August, and half-month rainfall erosivity of the second half of July got to the annual maximum value.(3) Over the entire province, the minimum value of average ten-year rainfall erosivity occurred in 1972-1981, and the maximum value was in 1982-1991, compared with that in 1982-1991, the average ten-year rainfall erosivity kept decrease in 1992-2001 and 2002-2011.(4) The average rainfall erosivity nearly 40 years had a strong spatial correlation. Average annual rainfall erosivity showed a parabolic distribution trends which direction was from west to east and from north to south within the scope of the province. It presented an obvious decreasing trend northward from Yilihuli Mountains, from east to west in Song-Nen Plain, from west to east in Sanjiang Plain, from south to north in Xiaoxing'an Mountains, and from north to south in Zhangguangcai Mountains and Laoye Mountains.