The invention discloses bacillus amyloliquefaciens B011 for preventing and treating tobacco bacterial wilt and an application thereof, and relates to the technical field of biological prevention and treatment of plant diseases, wherein the bacillus amyloliquefaciens B011 has the preservation number of CCTCC NO:M2014576; separation comprises the following steps: firstly, sampling; secondly, grinding, thirdly, centrifugation; fourth, purification, and fifthly, screening. The bacillus amyloliquefaciens B011 has the characteristics of relatively good antagonistic effect on tobacco bacterial wilt, good safety on the environment and easy industrialized production, not only can be used for preventing and treating tobacco bacterial wilt, but also can be used for preventing and treating P.parasitica, A.alternata keissler, also can be used for preventing and treating C.capsici, P.capsici, C.gloeosprioides, P.oryzae, C.cuc-umerinum and other pathogenic fungi.