The electrophoretic patterns of LDH isoenzymes in serum,eye,brain,o-vary,liver,skeletal muscle and cardiac muscle from adult M,anguillicaudatus expressed bythree dinds of body colours and distributed over rice field were studied by means of polyacry-lamide gel vertical electropheresis,The results indicated taht in these tissues there were twobands,namely LDH2 and LDH3,the activity of other LDH isoenzymes expressed low,evenno.The quantitative analysis exhibited a tissue specific expression in tissue distribution andenzyme-activity:the strongest activity of the LDH isoenzyme were LDH2 in brain,LDH3in other tissues,namely in serum,eye,ovary,liver and cardiac muscle.In addition,in liverthere was a C-band codied by Ldh-C.