Streptomycin-resistant mutants were obtained from original strains YH04 treated by UV (253 nm, 30 W, 45 s or 60 s) under the selection pressure of resistance to streptomycin (the lethal concentration is 1.2 mg/mL). Streptomyces Strain YH9407 with high antibiotic yield and genetic stability was obtained from streptomycin-resistant mutants. The yield of antibiotic TS99 is more than 60% higher than that of the original strain.