The invention provides bacillus velezensis and application of the bacillus velezensis as an aquatic pathogenic bacteria inhibitor. The bacillus velezensis is separated from the intestinal canal of healthy tilapia, and the preservation number of the bacterial strain is GDMCC No. 60344. The bacillus velezensis has a broad-spectrum antagonistic aquatic common pathogenic bacteria function, and has theadvantages that the growth of the pathogenic bacteria, such as streptococcus agalactiae, streptococcus iniae,nocardia seriolea, aeromonas hydrophila, aeromonas schubertii and edwardsiella tarda, canbe effectively inhibited, the use is safe, no residue is generated, reducing the usage amount and the residual amount of chemical drugs in aquaculture is facilitated, the production cost is reduced, and the practicality is strong.