The invention discloses the construction of a recombinant Bordetella bronchiseptica strain which does not contain a resistance marker and is used for expressing an ORF2 gene fragment of porcine circovirus type 2, the preparation of a vaccine and application, and belongs to the field of genetic engineering. The recombinant Bordetella bronchiseptica strain QH0814delta aroA/ORF2 which does not contain the resistance marker and is used for expressing the ORF2 gene fragment of the porcine circovirus type 2 is obtained. In the strain, a 5-enolpyruvyl-shikimate-3-phosphate synthase (aroA) gene of Bordetella bronchiseptica is deleted; and the strain contains the ORF2 gene fragment of the porcine circovirus type 2. The invention discloses the preparation of the recombinant strain and the vaccine and application of the recombinant strain and the vaccine to the preparation of porcine circovirus type 2 and porcine Bordetella bronchiseptica vaccines. The genetic engineering vaccine can stimulate pigs to produce the protective immune reaction of resisting the porcine circovirus type 2 and porcine Bordetella bronchiseptica wild strains, and can effectively prevent the porcine circovirus type 2 and porcine Bordetella bronchiseptica from infecting the pigs.