Abstract: The middle Jurassic Tunmen Formation volcanic rocks in Hong Kong mainly consist of andesitic lava, tuff and tuff breccias intercalated with tuffaceous sands. The tuff breccia, which has long been erroneously assumed to be sedimentary conglomerate, was determined as volcanogenic tuff breccias by Geological Sur- vey Group of Hong Kong since 1990. Based on petrography, it is found that the Tunmen Formation vol- canic rocks may be divided into andesitie-dacitic lava and explosion breccia of volcanic conduit facies, and tuff breccias of explosion airfall facies. Volcanic conduit facies may be further divided into volcanic neck fa- cies and dike facies which are distributed in both east and west of Tunmen Formation volcanic rocks. The volcanic neck cluster with NNW-trending intermittent and linear distribution is outcropped on the east foothill of Qingshan. The explosion breccia was identified incorrectly as sedimentogenic conglomerate in some geological works published in resent years, which induced some confusions in the process of geologi- cal exploration and engineering design and some economic losses. By summarizing latest research results and comparing with similar volcanic rocks of other regions in the world, it is identified that volcanic con- duit facies explosion breccia is existed and paleovolcanic neck cluster is characterized by linear distribution in Kong Hong.