[Objective] The aim was to identify microorganism against watermelon Fusarium wilt.[Method] The Fusarium oxysporum f.sp. niveum was taken as the research object and six strains with significant antagonistic activity to Fusarium oxysporum f.sp.niveum from symbiotic bacteria of marine sponges and soil samples were screened, and the six active strains was identified through molecular biological characteriza-tion.[ Result] The molecular biological characterization showed that these six active strains all belonged to Bacillus.[ Conclusion] The conclu-sion of this study lays a foundation for new type of safe and efficient biological pesticide and functional biological fertilizer towards watermelon wilt.