Using the 713 radar data and other meteorological observations, the charactersi-tics of the ambient field condition, satellite imagery and radar echo in the case of a severe squall line on 24th August of 1987 are analyzed in the paper.The important characteritics of the severe squall line activities in Beijing, Tianjin and Hebei Province in cold vortex patternn and some reference points for the nowcasting of squall line are presented here.