Numerous breccias were identified as the host rocks of the Pb-Zn polymetallic deposit in Changchengling area, Hunan Province. These breccias are restricted to the intersections between the granite porphyry dykes and the NE-striking faults. Their distribution patterns, compositions, textures, and alteration characteristics suggest that they might have resulted from cryptoexplosion. The cryptoexplosive breccias can be divided into explosive breccias, shatter breccias and mixed breccias on the basis of the features of the cryptoexplosive breccias. These breccias can also be divided into igneous cryptoexplosive breccias and hydrothermal cryptoexplosive breccias according to their genesis. The geological and geochemical features of the granite porphyries indicate that the early Yanshanian hapabyssal granite porphyries were rich in volatiles and experienced strong fluid-melt, thus probably belonging to the cryptoexplosion type. The cryptoexplosion provided not only ore-forming elements and fluids for the Pb-Zn polymetallic mineralization but also convergent and precipitable space for ore-forming fluids. The discovery of cryptoexplosive breccias connected with Pb-Zn polymetallic mineraliza- tion in the Changchengling orefield is significant in the search for deep-seated mineralization in this orefield as well as in the southern Hunan W-Sn polymetallic concentration area and even in the whole central segment of Nanling region.