Abstract: Using the newly designed culture medium for the cell and tissue culture of freshwater bivalves, the hemolymph from the oyster, Anodont woodiana pacifica(Heude), has been cultured in vitro. Four different kinds of hemocytes in the cultured hemolymph can be observed with phase contrast microscopy:agranulocytes, granulocytes, hyalinoctes and lymphoidocytes. Agranulocytes, granulocytes and hyalinocytes are fibroblast-like and can form long pseudlopods and extensions and adhere to the culture bottle wall tightly. Lymphoidocytes are always round and never adhere to the bottle wall. The proportion of the four kinds of hemocyte is 4:2:3:1. PHA and ConA were injected into the oyster before withdrawing the hemolymph, or these molecules were added to the culture medium of hemolymph, and the hemolymph were cultured for 2-7 days. Every day, part of the cultured hemolymph was taken out for the treatment of colchicine and hypotonic solution, and the observation of mitotic chromosomes by air-drying technique. However, no mitotic figure was observed. It can be concluded that the in vitro adhering properties of granulocytes, agranulocytes and hyalinocytes of the freshwater pearl oyster. Anodont woodiana pacifica, are the same as those of macrophages of the higher animal, and lymphoidocytes of the freshwater oyster, which never adhere to the bottle, morphologically like lymphocytes of the higher animal. All of the four kinds of hemocytes cannot proliferate when cultured in vitro, which is probably because they are highly differentiated cells.