Abstract: In order to investigate the mechanism of summer rainstorm occurred in southern Shandong Province and further improve the prediction accuracy, using conventional observation data, NCEP 1°×1° reanalysis data, FY-2E satellite TBB hourly data, the intensive observations of automatic weather station data, Doppler weather radar data and so on, a rainstorm process in southeastern area of Shandong Province was analyzed in detail. The results showed that the rainstorm occurred under favorable weather condition; the process that middlelevel dry cold air mixed with low-level warm air coming from a strong low-level warm advection and increased the atmosphere convective instability. The severe precipitation was produced when the lower positive vorticity increased while the upper and lower positive vorticity were superimposed. Storm center was closely related to the minimum value of the center and the strength of TBB. Doppler radar captured the cold air and strong echo activities during the heavy rain, and the heavy rainfall corresponded to two periods of heavy precipitation.