The invention relates to a porcine circovirus type 2 subunit vaccine, and a preparation method and an application thereof. The recombinant baculovirus contains double promoters (a polyhedrin protein promoter and a P10 promoter), and can express double copies of Cap protein coding genes, such that protein expression efficiency is substantially improved. Also, Cap protein expressed by an inserted exogenous gene does not contain excess sequences, such that virus-like particles (VLPs) can be effectively formed, expressed protein immunogenicity is improved, and the content of produced antigen is high. According to the porcine circovirus type 2 subunit vaccine provided by the invention, protein yield and quality of porcine circovirus type 2 subunit vaccine are substantially improved, and prepared vaccine compositions have the advantages of stable and long-lasting immune effect, high safety, and the like.