Determining the erosive rainfall standard of daily rainfall is an important prerequisite for improving the calculation accuracy of the simple model based on the daily rainfall. The standards of erosive daily rainfall in the Poyang Lake Basin were studied with the method of minimum deviation. The results showed that:(1) The erosive event rainfall standard in Poyang Lake Basin was 14.0 mm, where the coefficient deviation was 1.8%, the loss rate for erosion amount was 2.8% and the mixing index was 14.9%. (2) The monthly rainfall at each station was the highest rainfall in June with an inverted "V" shape; the type of rainfall time spanning two days or more was the most, accounting for 52.4% of the total erosive event rainfall. (3) The erosive daily rainfall standard in the Poyang Lake Basin was 10.0 mm, where the deviation value of the annual average rainfall erosivity between daily and event rainfall was 0.11%.