The patterns of aqueous soluble muscle protein of several species of freshwater fish were studied. To determine the proper sample sizes of each species ten fish species of the similar age picked at the same area were grouped. To study the differences of protein patterns in the each species the method of disc-electrophoresis using polyacrylamide was adapted. 1) The number of fish in each species tested was as follows; 21 Zacco platypus, 19 Microphysobio koreensis, 6 Pungtungia kerzi, 8 Tridentiger obscurus, 4 Cultriculus kneri, 3 Hemibarbus longirostris, 4 Sarcocheilichthys czerskii, 4 Carassius auratus, 5 Zacco temmincki, 16 Rhodeus ocellatus. The differences of the patterns within the species were not appeared. 2) In order to compare aqueous soluble muscle protein among species, the optimum quantity of each specie was appeared in 3 to 4 fish. 3) The number of bands of aqueous soluble muscle protein were 10 in Zacco platypus, 9 in Microphysogobio koreensis, 6 in Pungtungia herzi, 9 in Tridentiger obscurus, 8 in Cultriculus kneri, 10 in Hemibarbus longirostris, 10 in Carassius auratus, 7 in Zacco temnincki, 5 in Rhodeus ocellatus. 4) The number of bands, degree of stain, mobility and rate of contents were different in interspecies.