Herein,Phaffia rhodozyma wild-type strain(P.rhodozyma 02) was used as original strain to carry out two rounds of ultraviolet(UV)-LiCl and60Co-γ mutagenesis breeding successively.By using YM medium with 40μmol/L diphenylamine as screening agent,an astaxanthin high-yielding P.rhodozyma mutant strain H4-4 was screened,which was genetically stable and named as HSC-125.The volumetric productivity of astaxanthin of H4-4was 25.36 mg /L,which was 5.34 times higher than P.rhodozyma 02(4.75 mg /L).Two rounds of UV-LiCl and60Co-γ mutagenesis with diphenylamine as selection factor showed good results of breeding high astaxanthin-producing and genetically stable phaffia rhodozyma strains.