Abstract: Spinosad is a secondary metabolite with noticeable insecticidal activity maded from fermenta-tion of Saccharopolyspora spinosa.The spores of Saccharopolyspora spinosa were mutated with N-methyl-N' -nitro-N-nitrosoguanidin(MNNG),and the yields of spinosad were detected by HPLC.Results showed that positive mutants with larger proportion were obtained when the spores of the parental strain were treated 40 min using 2 mg/ml MNNG.As a result,five high-producing strains were selected,and their spinosad titers were increased by 61.1%,80.3%,128.1%,69.9%and 77.8%respectively.