Based on Chinese satellite in geosynchronous orbit (FY2C) information on cloud physical characteristics parameters of the retrieval,and observations by radar,microwave radiometer and precipitation on ground,the structural features of cloud merging of a strong precipitation process are analyzed in Anhui Province,China on 17 July 2008.Results show that the development of convective clouds merging is the main reason for the occurring of heavy precipitation.The cloud optical thickness retrieved by FY2C satellite is found to be well consistent with radar echo of the corresponding region and the evolution of surface precipitation distribution.The heavy rainfall areas are in good agreement with the those of big cloud optical thickness and strong radar echo.Cloud liquid water distribution is very uneven and mainly in group block structure.The top of clouds often merge in the initial stage of convective cloud merging.Once the uneven liquid water in clouds unites,the cloud optical thickness in the combined parts increases rapidly,the whole layer of liquid water content from the ground microwave radiometer changes dramatically,and the ground heavy precipitation occurs.The statistic result shows that the top of cloud rises,and its optical thickness often increases before the reinforcing of precipitation.If the top of cloud is high with small optical thickness value,precipitation on ground is usually not obvious.The optical thickness of cloud is more related to precipitation.In the initial period of convective clouds merging,the clouds base consists of small particles,showing a deep zone of diffusional growth on the map of 〖WTB1X〗Tr〖WTB1〗e relations.Then,the effective radius of cloud droplet of total layer significantly increases,and the mixed phase and glaciation temperature is warmer.