Abstract: This experiment was conducted to study Mx gene expression in E.coli under the condition of cloning Mx gene complete sequence. Chicken embryo fibroblast (CEF) were treated with poly I:C to stimulate Mx gene expression. Full length cDNA of Mx was cloned. Recombinant expression vector pGEXMx including Mx ORF was constructed using pGEX4t2 expression system to transfer Escherichia coli Rosetta (DE3) strain. The result showed that the relative molecular weight of expressed protein was about 75 ku after induction with IPTG, suggesting that Mx gene has been efficiently expressed. The research laid a good foundation for further studying on bioactivity assay, exploring new way of antiviral medication and transgenic study.