The invention relates to a method of producing a porcine pseudorabies virus antigen by a fully suspended cell culture. The method comprises the following steps: 1) recovering a BHK21 cell, performing suspension culture amplification with a shake flask, and inoculating the BHK21 cell to a reactor for suspended culture with a low-serum culture medium to obtain a suspension culture cell sap; 2) replacing the low-serum culture medium in the suspension culture cell sap with a serum-free culture medium for further cultivation, and performing exposure for virus culture; 3) continuously cultivating the BHK21 suspended cell for 96-144h till dead cell quantity reaches 90% above, harvesting the cell suspended liquid, freeze thawing, centrifugalizing and collecting the supernatant to obtain a virus liquid; and 4) concentrating, deactivating and degerming the virus liquid to obtain the porcine pseudorabies virus antigen. A porcine pseudorabies virus antigen vaccine obtained by the method is high in titer which is stabilized at 108.5TCID50/mL above, and the porcine pseudorabies virus antigen vaccine is high in purity and stable in quality, and the product quality is remarkably improved.