Abstract: A full-length cDNA of chicken Mx gene was obtained using reverse transcription polymerase chain reaction (RT-PCR) amplification of total RNA extracted from chicken embryo fibroblast (CEF) which was induced with Poly(I)·Poly(C). The RT-PCR product was subcloned into pMD19-T Simple Vector and mutagenesis was performed in PCR site-directed mutagenesis, sequencing analysis confirmed the successful mutation from G to A in the site 2 032 of chicken Mx cDNA. The fragments amplified by PCR containing the mutation site were subcloned into an eukaryotic expression vector, then transfected into COS-I cell. Enzyme, PCR and RT-PCR analysis indicated that the recombinant expression plasmid pcDNA3.0-MMx was successfully constructed, which may provide a basis of expression of Mx protein genes in vivo and in vitro and its specific biological activity research.