Abstract: In order to explore the effect of antagonistic microorganisms from the mud of Eleocharis dulcis(Burm.f.)Trin. ex Hensch. surface,the antagonistic bacteria were isolated from the mud with Escherichia coli and Staphylococcus aureus as indicator bacteria,and identified based on the morphologies,physiology,biochemistry and 16S rDNA. Besides,effects of their fermented filtrates on the microbial populations of Eleocharis dulcis(Burm.f.)Trin. ex Hensch. surface were determined. Results indicated that two antagonistic bacteria named WB22 and WB39 from the mud were identified as Bacillus amyloliquefaciens and Pseudomonas geniculata,respectively. The total bacteria,yeasts and molds from Eleocharis dulcis(Burm.f.)Trin. ex Hensch. surface were inhibited by two bacterial fermented filtrates. The inhibitory rate of B. amyloliquefaciens for bacteria,yeasts and molds was separately 17.42%,9.05% and 13.74%,and the cocci were more than bacillus,gram-positive bacteria more than gram-negative bacteria in the inhibited bacteria. While the inhibitory rate of P. geniculata for bacteria,yeasts and molds was separately 20.29%,4.64% and 16.14%,and the cocci,bacillus,gram-positive bacteria and gram-negative bacteria were all inhibited greatly. The research will provide theoretical foundation for the development of biological preservation technology of Eleocharis dulcis(Burm.f.)Trin. ex Hensch.