Abstract: Abstract: 4 strains of Entophytes were isolated from Cyperus rotundus L in this study, which were respectively belonged to Aspergillus(named XFf06.1 and XFf06.2)，Azotobacter Beijerinck(XFb)and Streptomyces(XFa).The result of detecting its antimicrobial activity showed that the product ion of the fermentative culture of the screened strains presented certain stable antimicrobial activity,especially XFa appeared highly antimicrobial activity to Bacillus subtilis and the antimicrobial activity of XFf06.1 to Apple cancer reached 96.3%.