Daily and event data from 8 weather stations was used to analyze the relationship between daily and event rainfall. The result showed that the difference was not marked, and it was feasible and reasonable to estimate erosivity using daily rainfall data instead of event data. The regression function of rainfall erosivity estimated from daily rainfall and the one from event data was 1∶1 line, and the average R-square of 8 stations was 0.950. Because the coefficient of the line was not different greatly in different climatic regions, an estimated rainfall erosivity model using daily rainfall amount and its maximum 10-min intensity was set up, and its R-square was 0.966 . This analysis will simplify the calculation of rainfall erosivity and stimulate the meteorological data application for soil erosion model.