LDH-A₄ (from muscle).LDH--B₄, (from heart) and LDH-C₄ (from liver) were isolated Tram grass carp by affinity chromatography. Their purifies,amino acid compositions and enzymatic dynamics were comparatively studied. It can be confirmed by the obvious differences of the amino acid composition that they are three different gene's products. In the meantime their relarant antibodies were respectively prepared, and. the typical and specific patterns of LDHs from same fish by the results of rantigenantibody immunoadsorption reactions were precisely determined, going further into the syng}en.ity between the LDH isazyme molecules of Carious source and the immunal syngenity of various LDH isozyme molecules.