Using the Parsivel laser precipitation particle spectrometer,3 617 samples of raindrop size distribution of Meiyu front rainstorm were observed in Huainan and Nanjing during summer of 2009—2010.Gamma raindrop size distribution function is fitted by moment method,and the micro-structure of Meiyu front rainstorm is analyzed.Results show that the sizes of precipitation drops in rain belt are larger than those on the edge of rain belt.Contributions to total number concentration of raindrops with diameter of 0.25—1.0 mm are the maximum,but those to total rainfall intensity of raindrops with diameter of 1.0—2.0 mm are the maximum.The raindrop size distributions of Meiyu front rainstorm mostly show double peak type,without non-peak type.The peak diameter of raindrop size distribution of Meiyu front rainstorm first increases and then decreases with the rainfall intensity.However,the parameters of Gamma distribution,N₀,μ and λ always decrease with the rainfall intensity,and there is a good binomial function relationship between μ and λ.In addition,the Z-R relationship of Meiyu front rainstorm is Z=212R^1.38.