In order to characterize the biological activity of fox (Vulpes vulpes) interferon gamma(VuIFN-g), We have isolated the cDNA encoding arctic fox(Alopex lagopus)VuIFN- g. This cDNA encodes a 23 amino acid signal peptide and a 144 amino acid mature protein, which shares 99.8% or 99.4% for nucleotide identity with silver fox and canine, respectively, and 100% for amino acid identity. Expression of recombinant mature arctic fox interferon gamma (mVuIFN-g) in bacterial system was confirmed by SDS-PAGE and Western blotting analysis. Recombinant VuIFN-g showed higher antiviral activity against vesicular stomatitis virus in cultured Vero and MDCK by inhibiting virus induced cytopathic effect, In view of the immunomodulatory and antiviral activities of VuIFN-g, it may provide a basis for further research on antiviral therapy of recombinant VuIFN-g in economic animal practice.