Abstract: The experimental study indicates that some ostracods are carnivorous,and thus may be considered as an effective predator for the schistosomiasis vector oncomelania.The rates of predation generally increase as a function of the amounts of ostracods.It is inferred from this reason that the ostracods may be used for biological controls on the schistosomiasis vector oncomelania aiming at the prevention of schistosomiasis.The ostracods may be re-produced rapidly,and increase in quantity to enough density in nature.