Porcine reproductive and respiratory syndrome virus chimeric recombinant vaccine strain and method for producing living vaccine with same

The invention relates to a porcine reproductive and respiratory syndrome virus chimeric recombinant vaccine strain and a method for producing living vaccine with same; latter half part of GP2 gene and GP3-GP5 gene of the porcine reproductive and respiratory syndrome virus (PRRSV) classic virus PTK strain, M ferritin, N ferritin and spacer sequences thereof and all nucleotide sequences of 3' non-coding region are all deleted by using reverse genetic manipulation and gene combination technology, then replaced with corresponding gene of Chinese highly pathogenic porcine reproductive and respiratory syndrome variant strain and are recombined to be the chimeric recombinant vaccine strain (PC strain) with the PRRSV classic strain and variant strain genes simultaneously, the chimeric recombinant vaccine PC strain is used to produce the living vaccine which has low toxicity, ensures no returning of strong toxicity within 5 generations of returning swine and the heritability is stable; the invention has good immunogenicity, and can prevent the porcine reproductive and respiratory syndrome virus classic strain and highly pathogenic variant strain from being infected simultaneously.