In order to ensure the biosafty of the IFN-γ antiviral activity assay, we used a replication-deficient VSV carrying GFP as an interferon sensitive indicator virus (VSV△G*G). The antiviral activities of porcine IFN-γ expressed in Escherichia coli and in baculovirus on MDBK cells were assessed. The results showed that the antiviral activity of porcine IFN-γ expressed in baculovirus could reach 105 IU/mL, while the porcine IFN-γ expressed in E. coli showed some antiviral activity (32 IU/mL) after refolding. The results of the VSV△G*G-based antiviral assay were almost identical to that of the VSV*GFP-based assay, suggesting it is highly feasible to use VSV△G*G as a substitute for VSV*GFP, making assays for IFN-γ antiviral activity safer and more accurate.