PRRSV recombinant antigen A1 inhibits the expression of CD163 on the cell surface by inducing the polarization of M1 macrophage subset, which can further effectively reduce virus invasionreduce infection. A1 can regulate the endogenous genes of alveolar macrophages to activate Th1-type immune responseenhance cellular immunity. Therefore, this technical invention will be beneficial to screen the new generation of PSSRV candidate structural vaccines.