Using surface observation, upper air sounding, satellite, Doppler radar and lightning data, synoptic scale environmental conditions and detailed mesoscale development analysis are undertaken on the severe convective system over Guangdong in the morning of April 17, 2011. Short time heavy rain, hail and squall were detected in this convective system, and results show that, the trigger of severe convective storms is the cold front, and meanwhile the local topography of the Pearl River Delta, mid level jet over Guangdong and large wind shear are considerably important in maintaining and developing of the storm. In the last, analysis and summary of subjective forecasting in this weather system are also given.