Abundant conodonts occur in the Naqing section, southern Guizhou, South China, which has been selected as the candidate of the Carboniferous Kasimovian GSSP. Swadelina subexcelsa, Idiognathodus heckeli, I. turbatus and I. sagittalis, which are potentially index taxa for the Moscovian-Kasimovian boundary, are all recorded in the Naqing section. The lineages from their ancestors have been discussed in this paper, and furthermore, based on their lineages the conodont zonation is established for the global correlation. The provincialism of the Moscovian-Kasimovian boundary interval is also analyzed. The Tethyan and American Midcontinent provinces, can be identified to differentiate conodont faunas among major basins. The Tethyan Province can be further subdivided into the South China and Eastern European Platform subprovinces. By incorporating and evaluating varying aspects of the taxonomy, biostratigraphy and palaeobiogeography of the potential index taxa, I. heckeli might be the best marker for the base Kasimovian in term of its clear taxonomic definition and phylogenetic lineage, as well as its wide geographic range.