Abstract: Actinomycetes were isolated from the gastrointestinal tract of four kinds of marine animals by classical culturing technique.Actinomycetes was primarily screened with the method of UV- visible spectrometry to detect the antioxidant activity,then four radical scavenging( DPPH radical,hydroxyl radical,superoxide radical and alkyl radical) were further determined by JES- FA electron spin resonance( ESR) spectrometer.Finally,strains with higher antioxidant activity were identified by 16 S r DNA. Results showed that 37 actinomycetes were acquired,and DPPH radical scavenging rates of seven strains were found over 50% by primarily screening method,and DPPH radical scavenging,hydroxyl radical scavenging,superoxide radical scavenging,alkyl radical scavenging of CH16 and CH38 were higher than 50% by ESR method. Also the strain CH16 and CH38 were identified as Amycolatopsis rifamycinica and Amycolatopsis sp.,respectively. This research can provide reference for collecting having antioxidant activity marine actinomycetes resource and further development.