Based on a petrologic and geochemical analysis of Permian volcanic rocks in the study area, this paper attempts to clarify the palaeo-tectonic setting and provides independent evidence for understanding the nature of the basin. The data show not only the characteristics of an intraplate setting on the whole but also the signature of a subduction zone. Combined with the sedimentary formation characteristics, the authors have reached the conclusion that the Permian magmatic activity of the study area was generated in an intraplate setting, with variable degrees of contamination of the crust during magmatic ascending, related probably to the mantle plume event.