A severe hail event occurred in the south of Shenyang in 21 August 20011 is studied by using automatic weather station data, weather map, T lgp map, mosaic and ROSE products, and the evolvement and structure of the severe hail are analyzed in detail. The results demonstrate that the severe hail occurred under the background of an upper level trough and wind convergence. The characteristics of CAPE, vertical wind shear, and radar echoes all indicate that there were favorable conditions for the occurrence of severe hail. Some indexes are put forward for severe hail nowcasting by means of derived radar products before and after the hail.