Using the precipitation phenomenon instrument data, combined with the Doppler weather radar data and the ERA5 2.5°×2.5° reanalysis data, the radar echo and raindrop size distribution characteristics of the heavy rain in Yinan, Shandong province from August 13 to 14, 2020 are analyzed. The main conclusions are as follows.( 1) The precipitation in Yinan includes a relatively complex evolution process of radar echoes. The squall line and the linear convection on the right front merge near Yinan. The earlier precipitation in the Yinan is generated by the linear convection and discontinuous convection echoes at the tail of the squall line (referred to as the squall line precipitation), and the later heavy precipitation is generated by the continuously developed and strengthened mesoscale convective cloud cluster (referred to as convective cloud cluster precipitation).(2) The main feature of the raindrop size distribution of the squall line precipitation and the convective cloud cluster precipitation with different rain rates is that the density of larger particle number increases faster as the increase of rain rate. The main difference is that when the rain rate R>100 mm?h-1, the increase in density of small and medium particles with a diameter of less than 3.0 mm is the main factor for the increase in the rain rate of the squall line precipitation.(3) The analysis of the normalized Gamma function parameters lgNw and Dm demonstrates that Dm increases gradually, while lgNw increases slightly with the increase of rain rate. That indicates that the main factor for the increase in rain rate of the squall line precipitation and the convective cloud cluster precipitationis the Dm change. On the other hand, lgNw change is the secondary factor. The convective cloud cluster precipitationh as slightly larger Dm and lgNw values, and the Z-R relationship of the convective precipitation has a larger exponent, which indicates that the raindrop size distribution of the convective cloud cluster precipitation is closer to the raindrop size-controlled distribution. The parameter of distribution lgNw-Dm indicates that both the squall line precipitation and the convective cloud cluster precipitation correspond to the feature of the raindrop size distribution in continental convective precipitation. However, the distribution range of the squall line precipitation parameters is larger, which indicates that the formation mechanism of raindrops is more complicated.