Disclosed are an attenuated live vaccine against mycoplasmal pneumonia of swine (MPS) and use thereof. In the present invention, pathological lung tissues of swine having typical Mycoplasma hyopneumoniae (Mhp) infection and no obvious other pathogenic infections are screened, and subcultured 100 generations in lungs of newborn rabbits； then, Mhp strains are isolated and serially subcultured in a medium； and the Mhp strain AN306 is obtained by screening a plurality of strains, which is deposited with an accession number: CCTCC NO. M2012431. Also disclosed is a live vaccine formulation against MPS prepared on the basis of the attenuated strain and comprising live attenuated strain, a pharmaceutically acceptable carrier or excipient, and optionally an adjuvant and immunogens of other pathogens.
