To enhance the understanding of cloud microphysical structures in eastern Guizhou and provide a basis for determining aircraft_based artificial precipitation enhancement conditions, we conducted penetration observations of cumulus_stratiform mixed cloud systems over eastern Guizhou on 26 May 2024 using large unmanned aerial vehicles (UAVs) equipped with detection instruments, and here analyze the microphysical characteristics of the cloud systems during the detection process. The results show that large UAVs are adaptable to complex terrain. With a quick response, they can effectively carry out observations and transmit data in real time, providing guidance for locating potential precipitation enhancement areas. Observations revealed numerous small cloud droplets which have high concentration and small diameters, but fewer large cloud and precipitation particles with low concentration and large diameters. In the area with radar reflectivity ≥25 dBz, the concentration of small cloud particles increased to 253. 5 per/cm3, the effective diameters of large cloud particles increased to 460 μm, and the effective diameters of precipitation particles reached 1 092 μm, reflecting the growth of ice crystals that involve condensation, agglomeration and highly efficient collision growth. During Period 1, there was less supercooled water in the clouds, the ice_phase process was weak, and the precipitation potential was low. Cloud droplets mainly grew through homogeneous condensation. During Period 2, the content of supercooled water in the clouds was relatively high, the concentration of large particles was added, the clouds were in a mixed_phase state, and the growth of particles was limited. In Period 3, the enrichment degree of supercooled water in the clouds was the highest, with large particles dominating. The growth of particles was mainly driven by deposition, riming and aggregation, resulting in high precipitation efficiency. The systematic differences in cloud microphysical structure in different cloud system zones and detection periods have revealed the typical characteristics of cloud_water phases, particle growth mechanisms, and precipitation formation efficiency. These findings can be a direct observational basis for an in_depth understanding of the characteristics of the cloud system in eastern Guizhou and for analyzing the seeding conditions of artificial rain enhancement.