An analysis is made of the structural characteristics of the convective clouds and precipitation on 25 to 26 June in 2005, by using a variety of observation and remote sensing data and the favorable surrounding conditions by using NCEP reanalysis data and real wind data. The results show that some mesoscale convective cloud clusters underwent the development of more than 10 hours, and TBB decreased to －90 degrees，which led to the inhomogeneous rainfall distribution in both time and space. The convective clouds had prominent microphysical structural characteristics, which had the high content of ice particles at the upper level and more plentiful cloud water. The seederfeeder mechanism was playing the major role. The “doublepeek” profile structure of convective precipitation shows that the warm rain process was very strong in MCC. The surrounding conditions were very useful for the formation of MCC and the convective storm： the water vapor transmitted and converged by the strong southwest low level jet and the interaction of high and low level jet provided vapor and unstable conditions；the strong vertical upward motion in the unstable areas was the necessary dynamic condition；the middlescale convergence system directly caused the convective process.