Based on the precipitation phenomenon instrument data, combined with the Doppler weather radar data and ERA5 data (0.25°×0.25°), the synoptic systems, radar echoes and raindrop size distribution characteristics of the severe rainstorm in Yinan, Shandong from 13 to 14 August 2020 are analyzed. The main conclusions are as follows. (1) The precipitation in Yinan includes a relatively complex evolution process of mesoscale echoes. The earlier precipitation, referred to as the squall line precipitation, is generated by the linear convection and discontinuous convection echoes at the tail of the squall line under the influence of cold air and a low-level shear line, and the echoes strongly develop. Generated by the continuously developed and strengthened mesoscale convective cloud cluster, the later heavy precipitation, referred to as convective cloud cluster precipitation, is a kind of precipitation within the warm sector of the southwest low-level jet at the edge of the subtropical high, and the echo intensity is weaker with longer duration of precipitation. (2) The squall line precipitation is highly localized with a great fluctuation of rainfall intensity, and there are obvious changes in the parameters of lg N_w, Dmand N_T. In contrast, the convective cloud cluster precipitation is relatively stable with slight changes in the parameters of raindrop size distribution, resulting in a more concentrated distribution of lg N_w-D_m Both types of precipitation exhibit the raindrop size distribution characteristics of continental convective precipitation. (3) During the squall line precipitation, the coalescence and collision-breakup processes are more likely to reach equilibrium, and the proportion of equilibrium raindrop size distribution is high. During the convective cloud cluster precipitation, the proportion of transitional raindrop size distribution is high, indicating that the crushing of raindrops has a significant impact on the ground raindrop size distribution, which obviously alters the raindrop size distribution. Overall, there are certain but not significant differences in the microphysical characteristics of heavy precipitation in cold and warm sectors.