Abstract: The genetic inactivation of eggs is one of the key techniques in fish anadrogenesis.The present paper deals with ultraviolet (UV) rays irradiating for genetic inactivation of loach (Misgurnus Angullicaudatus and Paramisgurnus dabryanus) eggs.Five treatments of irradiation were examined, including irradiating the eggs with solution-free, synthetic o-varian fluid (OF), TC-199 solution, Ringer's solution, and Holtfreter's solution.The results showed that high yield of hyploid was induced for the eggs stored in all solutions at total energy of irradiation ranged 90-180mJ/cm2.The rtional dosages of UV irradiation were from 120 to 180mJ/cm2 in OF, 120mJ/cm2 in TC-199 and in Renger's solution.The inactivating effect of female nucleus was found best when irradiating the eggs stored in OF, then decreased subsequently when the eggs stored in TC-199 solution, Ringer s solution, Holte-freter s solution, and solution-free.