Abstract: Using synoptic chart, numerical forecast product and Doppler radar to analyze the weakened tropical depression of typhoon“Haitang”, the author studied the severe convective weather process in Weifang of August 2 to 3, 2017, which was caused by typhoon“Haitang”. The results showed that: (1) this severe convective weather process was mainly caused by the weakened tropical depression of typhoon, cold air and ground cyclone; the good dynamic lifting condition, nice vapor transport condition and train effect caused rainstorm and heavy rainstorm in many sites of Weifang; (2) the severe numerical forecast products had great difference in the prediction of this process, the European Central numerical model showed great performance and could guide future forecast.