Marine mammals, 41 species in total including 8 species of Mysticeti, 27 species of Odontoceti, 5 species of Pinnipedia and only 1 species of Sirenia have been known and recorded in China. According to the number of species of China marine mammals in each natural sea area, the Bohai Sea possesses only 9 species, accounting for the least, whereas the species in the South China Sea has the most abundant, existing 28 species. In comparison with Taiwan Province, 32 species distribute along the coast of mainland, and 30 species along the coast of Taiwan Province. Some species with rather strong Torrid Zone nature apparently represent the fauna of marine mammals in the southern sea area. Cold-warm species coming from the frost sea area represent the fauna of marine mammals in the northern sea area.