Abstract: In the report， the observation data of the raindrop size distribution in Tunchang of Hainan Province were used to analyze the typical precipitation processes of convective clouds， stratiform clouds and stratified mixed clouds respectively. The results showed that the three types of cloud precipitation are dominated by raindrops with a diameter of less than 1 mm， and the raindrops with a diameter of 1-3 mm contribute to the most of the precipitation， the concentration of large raindrops with a diameter greater than 3 mm in convective clouds is only 0.77%， and whose contribution to the rain intensity is 27.12%. The evolution of microphysical parameters and raindrop size distribution of convective clouds fluctuates greatly， the spectrum width is wider， the spectrum structure is single peak， the concentration of raindrops with a diameter of less than 1 mm increases rapidly when the rain intensity increases， and occurs frequently with large raindrops with a diameter above 4 mm； the evolution of microphysical parameters and raindrop size distribution of stratiform clouds fluctuates gently， the spectrum width is narrow， the single peak is dominant； the evolution of microphysical parameters and raindrop size distribution of stratified mixed clouds have the precipitation characteristics of both convective clouds and stratiform clouds. The raindrop size distribution of three types of cloud precipitation conform to the Gamma distribution characteristics， and the Z-I relationship obtained by statistics is better than the general formula， which provides a reference for the quantitative estimation of precipitation and disaster warning by radar in the area.