Although the Neophocaena is currently thought to be monotypic (¡§Neophocaena phocaenoides¡¨) with three ¡§subspecies¡¨, the taxonomy of this genus still remains uncertainty. The finless porpoise (¡§Neophocaena phocaenoides¡¨) is one of the small cetacean species under threats from human activities. At present, finless porpoise is listed in Appendix I of Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). For conservation issue, it is important to define appropriate and unambiguous ¡§units¡¨. In this study, I intended to settle the taxonomic status of the specimens of finless porpoise from the southern part of the East China Sea (including the Taiwan Strait) in which the status has been under debate. Results from this study, indicated that they should belong to ¡§N. p. sunameri¡¨. Comparing the genotypes of the microsatellite of additional individuals of the ¡§N. p. asiaeorientalis¡¨ belonging to the VN-type group given in Xia and coworkers report with our data, three distinguished genetic groups were revealed: (1) the group occurring in the Taiwan Strait (i.e., the W-type group, currently recognized as ¡§N. p. phocaenoides¡¨); (2) the group occurred in the Yangtze Rive (i.e., the VN-type group, currently recognized as ¡§N. p. asiaeorientalis¡¨); (3) the group occurred in the Yellow Sea and the Taiwan strait (i.e., the IN-type + UN-type group, currently recognized as ¡§N. p. sunameri¡¨). Population differentiation was absent not only within the W-type group but also within the IN-type +UN-type group. I tried to detect the taxonomy of the two parapatric groups in where the W-type and IN-type +UN-type groups are co-exit sympatrically. No specimens with intermediate character state of the width of the dorsal denticles (i. e., hybrids) were presented in Matsu Islands on the Chinese coast where the W-type and UN-type groups were sympatric. Hybrid individual exhibiting the hybrid states of the 11 microsatellite loci between these two groups was also not found. According to E.O. Wiley¡¦s criteria for recognizing species, these two groups are eligible to be considered separate species. Based on Crandall and his coworkers¡¦ criteria of evolutionarily significant unit (ESU), the three groups, the W-type, IN-type +UN-type and VN-type groups, should be treated as three distinct ESUs.