In Studying the benthic oysters and fouling organisms of the China Seas in the last years,we found four species, which are recorded for the first time from the China Seas. The species Neopycnodonte cochlear (Poli, 1795), collected from the East China Sea, is replaced in the Pycnodonteidae; other three species Alecryonella plicatula (Gmelin, 1791),Nanostrea exigua Harry, 1985 and Crassostrea nippona (Seki, 1934) belonging to the Ostreidae were collected from the South China Sea, the Ease China Sea, and the Bohai Gulf, respectively.