Abstract: In this paper, FY-4 meteorological satellite single channel cloud map and multi-channel combination are used to analyze the evolution and microscopic physical properties of the rainstorm cloud system, taking the process of a heavy rainstorm in sichuan basin on July 28, 2019 as an example, The results show that in this rainstorm, multiple convective cloud clusters merge for many times, and the combination of cloud clusters results in the increase of rainstorm area and intensity,There is strong large-scale vertical upward movement in the rainstorm cloud, and the whole atmosphere is full of water vapor, which provides better water vapor transportation and dynamic conditions for heavy rainfall.The multi-channel RGB cloud map can highlight the convective system, cold and warm air mass, cloud particle phase state and other attributes in the form of color.?The convective cloud ?that caused this rainstorm is mainly composed of ice particles composed of cumulonimbus clouds with strong updraft.FY-4 meteorological satellite plays an important role in monitoring mesoscale severe convective weather such as rainstorm, which complements the shortage of conventional weather data analysis and provides an idea for short-term weather prediction.