The invention relates to a vibrio alginolyticus strain and application thereof, in particular to the Vibrio alginolyticus SSL073 strain with the collection number of CCTCC M 2010193. The Vibrio alginolyticus SSL073 powder prepared from the strain can be used for enhancing the immunization level of prawn cells and body fluid. The Vibrio alginolyticus SSL073 strain is screened from prawn alimentarycanal, is an endogenic strain, has multiple biological functions of remarkably improving the nonspecific immunization level of cultured prawn, greatly enhancing the pathogen infection resistance of the cultured prawn, particularly remarkably improving the capability of resisting pathogen infection of the prawn and the like.