A molecular phylogenetic study was conducted on genus Grandinenia, based on COI and 16S sequences. A total of eight out of 26 species in the genus, as well as three unidentified species were sequenced. Phylogenetic results supported the monophyly of Grandinenia and the validity of all sampled species and subspecies. A new species, Grandinenia jiangjilini Chen, Lin, Wu & Ouyang, sp. nov., from Guangxi, southern China is identified and described, based on morphological comparison and molecular phylogeny. The discovery indicates that the inflated-fusiform shell is not isolated in genus Grandinenia and the species diversity of the genus still remains to be explored.