Based on the hazardous weather reports, disaster telegraph data and NCEP 1°×1° reanalysis data from 175 stations in the Beijing, Tianjin and Hebei (HTB) areas from May to September from 2001 to 2008, the synoptic circulation patterns in the HTB area from May to September, which is objectively divided into four types by using the SelfOrganizing Maps (SOM) method, are identified, and the synoptic characteristics and main severe convective weather types of each synoptic pattern are analyzed. The results indicate that: (1) There are four cluster types of synoptic patterns in the BTH area: the Warm and Wet (WWS) pattern, in which shorttime rainstorms occur mainly in July and August; the Cold Vortex (CV) pattern, in which hails accompanied by shorttime rainstorms and gales occur mainly in June and July; the Northwest Airflow (NA) pattern, in which gales occur mainly in May; and the West Wind Trough (WWT) pattern, in which gales and shorttime rainstorms occur mainly in June and September. （2）The main features of the WWS pattern include warm and humid at low levels, superimposed by dry and cold northwest flow, sufficient water vapor transmission, and strong stratification instability； the main features of the CV pattern include the strong inrush of arid cold air in the middlehigh layer from a stronger northerly airflow and good moisture condition at low levels; the main features of the NA pattern include the strong inrush of arid cold air in the middlehigh layer and strong vertical wind shear； the features of the WWT pattern are not obvious. （3）The NA and CV patterns have the highest frequency of severe convective weather, more than 65%, and the WWS pattern comes second, followed by WWT pattern.