Abstract: To research effect of admixture of cordyceps culture medium of different percentage on main organ weight and organ coefficients in SPF Wistar rat. We measured body weight, weight of heart, liver, spleen, lung, kidney, adrenal gland, testicle, ovary and stomach of Wistar rat in each group by electronic scale, and computed their organ coefficients. Results: It do not exist significant difference for body weight of Wistar rat of same sexes among different groups; Organ weight of heart, lung and testicle of males and lung of females in Wistar rat of lowpercentage group are higher remarkably than control group’s and highpercentage group’s; Organ coefficient of of heart, lung, kidney and testicle of males and heart, liver, lung, kidney and stomach of females in Wistar rat of lowpercentage group are higher remarkly than control group’s and highpercentage group’s; Weight and its coefficient of adrenal gland of males of low & highpercentage group and it of female in Wistar rat are notably lower than control group’s. Conclusion: premix of Cordyceps culture medium of suitable percentage can use for basic feed of laboratory animal in rodents, but it is await for farther experimental research whether or not is fit for other animal. 

Key words: admixture of cordyceps culture medium; SPF Wistar rat; organ coefficient