Based on meteorological observational data and WRF model products, the severe convective weather process at Baiyun airport on April 1 7, 2007 was analyzed. The results show that the strengthening of southwest monso on and the establishment of the lowlevel jet create the sufficient vapor and u nstable condition in South China. The lifts of cold front and terrain promote the formation and development of convective weather. The precipitation of model out puts and Radar echo have a good instruction to the aviation security.