Bacillus pumilus bacterial strain application thereof

The invention aims to provide a bacillus pumilus bacterial strain of which the preservation number is CCTCC M2013263. The bacillus pumilus disclosed by the invention can improve the composition and the number of dominant microbial populations in an alimentary canal of a prawn to form and maintain good microecological balance of the alimentary canal, and withstand the adhesion and the proliferation of viruses in the alimentary canal through competition for nutrition, competition for space or secretion of bacteriocin and the like. The bacillus pumilus can activate the expression of prophenoloxidase, superoxide dismutase, lysozyme, heat shock protein, lipopolysaccharide-glucan conjugated protein, signal transduction and transcriptional activation factors and the like of the prawn with relevant pathogenic infection resistant molecules, and retard the proliferation rate of the viruses in the body of the prawn. The bacillus pumilus disclosed by the invention can be added to raw materials of a prawn feed, and can also be directly applied to the prawn breeding water environment.