Based on the observation data from CINRAD/SA radar combined with ground observation and sounding data, 7 severe convective storms triggered by mesoscale convergence lines are analyzed. The results are as follows. 1) Boundary layer convergence lines such as gust fronts, sea breeze fronts and cold fronts are manifested as distinct narrow-band echoes on radar reflectivity products under certain environmental conditions. Some of the mesoscale convergence lines cannot get any useful information from radar reflectivity products, but can identify linear convergence zones of radial velocity for low-level radial velocity. 2) The first convective thunderstorm principally appears about an hour after narrow-band echoes or distinct radial convergence lines are identified by the radar. 3) For the gust front generated by dry-type severe convective storms, its right side is usually the main area of triggering new convection cells, leading to the rightward propagation of new storms. 4) For wet-type severe convective storms, the direction of new convection cells triggered by the gust front tends to be opposite to the average moving direction of thunderstorms, leading to the back-propagation of new storms. 5) The main area of triggering new convection cells lies where the sea breeze front is advancing rapidly inland, and the subsequent thunderstorms have the characteristics of bilateral propagation. 6) The low-level linear radial velocity convergence line in appropriate environmental conditions can trigger convection cells and the convective storm moves slowly, which can cause local disastrous heavy rainfall events.