Based on data of THIES disdrometer and CINRADA/SA Doppler radar, the raindrop size distribution and integral parameters of convective precipitation in two mesoscale system,whose maximum rain intensity were 483.0 and 418.9mmh-1 respectively, were analyzed. The results shows that:The two precipitation processes wereboth affected by the southwest airflowoutside the subtropical high and the westerly trough withthe characteristics of high temperature and high humidity, which were conducive to the production of heavy rain. On August 3, 2015, the echodeveloped more strongly and was in the mature and weakened stage near the observation point.On July 26, 2017,two linear mesoscale convective echoeswere merged near the observation point, and the echo was in the stage of development and enhancement.In severe convective precipitation episode (rain intensity R>20 mmh-1), for the raindrop concentration (NT), the exponential function can be used to fit theNT with the increase of R. On August 3, there was a large coefficient and a small index, while on July 26, it was just the opposite. For the the median volume diameter of the raindrop, on August 3, D0 rapidly increased with the increase of R, and the slope of the fitting line was large, whilelgNw gradually decreased with the increase of R. On July 26, D0 and lgNware both positively correlated with R, but D0 increased slowly with the increase of R, and the slope of the fitting line was small. For the Z-R relationship, the precipitation on August 3 had a smaller coefficient and a larger index, while the precipitation on July 26 had a larger coefficient and a smaller index. For the characteristics of mean raindrop size distribution of convective precipitation at different rainfall intensities, On August 3, when the rain intensity was more than 100 mmh-1, the particle number density of large raindrops with a diameter of 3-6 mm increased significantly with the increase of the rain intensity. On July 26, the number density of raindrops in each diameter range increased with the increase of rainfall intensity. In conclusion, based on the relationship between integral parameters and rain intensity and the average raindrop size distribution, the precipitation on August 3 was the typical size controlled raindrop size distribution characteristics, while the convective precipitation on July 26 was the concentration-diameter mixed controlled raindrop size distribution characteristics.The NW-D0 distribution of the normalized Gamma function showed that the convective precipitation of the two cases had the characteristics of typical rain drop size distribution of continental convective precipitation. Many raindrop size distribution in the processes of August 3 showed the characteristics of ice phase and warm rain mixed convective precipitation, but most of the convective precipitation in the two processes had the rain drop size distribution characteristics of ice-based.