Abstract: The Carboniferous System of Nanxi is a key window for the study of the Mesozoic volcanic rocks along the coasts of southeastern China. Through a detailed analysis of the Carboniferous stratigraphy, biostratigraphy, lithofacies and sedimentary environment of the area, the authors suggest that the Carboniferous is not the product of the Hercynian geosyncline but an allochthon.