The invention relates to a vaccine strain of HIN1 swine influenza virus, wherein a classification naming is Swine influenza virus A/Swine/Nanjing/50/2011 (H1N1), and a microbial accession number is CCTCC NO: V201218. According to the invention, isolation, identification and whole genome sequencing of the HIN1 swine influenza virus strain are carried out, and an inactivated vaccine against the swine flu is prepared by using the HIN1 swine influenza virus strain. The inactivated vaccine against the H1NI swine flu prepared from the virus strain can provide good protection for pigs attacked by homologous virulent strains, has good immunogenicity, and can effectively prevent H1NI swine flu with single vaccine or combined vaccines.