In this paper, methods of data processing and quality control were put forward according to the power spectral and raindrop spectrograph data from the Ka-band millimeter-wave cloud radar in the third Tibetan Plateau Experiment of Atmospheric Sciences Project. The usual physical quantum and the unusual quantum in domestic were also calculated, such as the spectral skewness, spectral kurtosis, average falling terminal velocity of particles and atmospheric vertical velocity. These physical quantities were used to analyze vertical structures and microphysics process of the convective cloud-precipitation over the Tibetan Plateau （Naqu） on 16 July 2015. The results are as follows: （1） The falling graupel convective clouds of the Tibetan Plateau were the strongest from 16:00 to 17:00 Beijing Time （BT） with similar structures as the hail clouds in low altitude. （2） In the same convective cloud, when it was graupel, the spectral skewness varied from “positive-negative- positive-negative” to negative; spectral kurtosis varied from negative to zero; particles in the clouds were tended to be round. （3） When the speed of updraft was greater than or equal to 6 m/s in supercooled water layer（-17~-7℃）, the graupel particles , which were formed into ice crystal accretion with supercooled water drops and rimming growth, were larger than that less than or equal to 4 m/s, in the convective clouds. （4） In the convective clouds, ice crystal and graupel melt in the up-side region 300 m above 0℃ level.