The invention belongs to the field of veterinary vaccines, particularly relates to a quad inactivated vaccine of PCV2-type baculovirus, swine mycoplasma hyopneumoniae, a porcine influenza virus and haemophilus parasuis and further discloses a preparation method for the quad inactivated vaccine and application of the quad inactivated vaccine. The quad inactivated vaccine disclosed by the inventioncontains inactivated protein Cap expressed by the PCV2-type baculovirus, inactivated swine mycoplasma hyopneumoniae, an inactivated porcine influenza virus H1N1subtype virus, inactivated haemophilus parasuis types 4, 5 and 13 and an adjuvant of the vaccine; four kinds of antigens are free of interference to one another, four kinds of protection can be achieved by one injection, and four kinds of epidemic diseases can be prevented through one-time immunization; and meanwhile, in view of toxic substance counteracting protection and serum antibody level, the immunization effect reaches or exceedsthat of each single commodity vaccine, the immunization duration is long, the efficacy is durable, and the quad inactivated vaccine has the advantages that the safety is good, the preparation methodis simple, the immunization is convenient, the immunization cost is reduced, and the like.