Abstract: In order to screen out avermectin high-yield strains,improve the fermentation unit of Streptomyces avermectin and reduce the production cost,the dual screening method of UV mutation combined with different types of antibiotics was used to screen the original strain AW-8.The results showed that,a total of 16 strains with high production of streptomycin monoclonal antibody were screened out,the positive mutation rate was10.7%;27 strains with high production of rifampicin monoclonal antibody were screened out,the positive mutation rate was 14.2%;6 strains with high production of streptomycin and rifampicin double antibody were screened out,the positive mutation rate was 5%.A high and stable streptomycin and rifampicin resistant strain R4 was obtained.The titer of R4 was 8.53% higher than that of W7 and 20.92% higher than that of AW-8.This method is a convenient and effective breeding method.