Abstract: ObjectiveAntagonistic bacteria with strong antagonistic effect to fusarium wilt of melon was screened and identified to provide reference for enriching the resources of biocontrol bacteria against melon fusarium wilt in tropi-cal zone.MethodEighty-two strains obtained in preliminary screening were used as experimental material,and antago-nistic bacteria against melon fusarium wilt were screened by using plate confront culture,successive transfer culture,ger-mination experiment and pot experiment. The strains were classified through characteristics in morphology,physiology and biochemistry and information of 16S rDNA.ResultA strain of actinomycetes D2 with strong antagonistic effect to melon fusarium wilt was screened and it had 73.53% control efficiency to fusarium wit of muskmelon. Strain D2 would form aerial hyphae and fibrillae of spores,and fibrillae of spores were spiral,and spore eggs were round. Strain D2 and Streptomyces lydicus were clustered in the same branch with 99.6% homology. Taking the morphological characters and physiological and biochemical characters of strain D2 into consideration,strain D2 was finally identified as S. lydicus.ConclusionStrain D2 has strong antagonistic effect to fusarium wilt of melon and worth to be developed as biological pesticides and fertilizers.