The invention relates to a method for efficiently extracting hemolymph of bivalve. The method includes the following steps that a, seawater on the surface of the bivalve is completely absorbed through cotton balls, the surface of the bivalve is wiped with ethyl alcohol to be sterilized, and seawater on the surface of the bivalve is completely sucked up through cotton balls; b, the bivalve which is completely wiped is placed in a groove of an extracting device, the adductor muscle of the bivalve is ripped open, a shell is open, and two shells are flatly open and erected in the groove; c, after pelecypod of the bivalve and the portion below a water pipe are cushioned with cotton balls, an outer sleeve membrane above a pericardial cavity is slightly shifted away through tweezers, and the pericardial cavity is completely exposed; d, a gun head of a liquid moving device is cut, meanwhile, the pelecypod of the bivalve is stimulated, and hemolymph is fast sucked with the liquid moving device when the heart beats and the pericardial cavity swells. The method has the advantages that the method is easy to operate, the total amount of the extracted hemolymph of the bivalve can be effectively increased, the purity of the hemolymph is improved, and the operating environment can be kept clean in the operating process.