101 strains of original Actinomyces spp. were isolated from soils composted with barnyard manure, and 16 strains with definite antagonistic effect were selected from 28 random strains by laboratory antagonistic test. The results of pot-culture control test using 6 strains with good antagonistic effect and A15 strains with less inhibition zone and greater colony showed that prevention effect of A6 strain was the best, up to 55.26%, and that of the other strains was less.