Abstract: Based on the analysis of the characteristics of Qianjiang radar data in recent years, some common characteristics of short-term heavy precipitation, hail, thunderstorm and strong wind are summarized, which are used as the threshold criterion of radar automatic alarm. Based on radar based data, through binarization processing of radar echo, mean filtering, opening operation and closing operation, a single echo connection area is separated by region growth method, and the characteristics of each echo connection area are analyzed and calculated automatically, so as to realize automatic recognition, tracking and early warning of radar echo, and effectively improve the ability of short time early warning of severe convective weather.