【Objective】This study was conducted to explore a highly efficient chicken gene engineering antiviral agent to prevent and control the chicken viral disease. A recombinant plasmid pET28a-rChIFNα-IL18 was constructed，which was expressed in Escherichia coli， purified by Ni-NTA and tested for antiviral bioactivitiy. 【Method】 This study introduced a novel method for constructing vectors by fusion PCR， which generated PCR products with overlapping chain using Primers complementary to the end. Through the extension of PCR products， ChIFN-α and ChIL-18 constituted the ChIFN-α-ChIL-18 fusion gene when cloned into the vector pET-28a， induced the expression in E. coli strain BL21（DE3）. This protein was purified by Ni-NTA and detected by SDS-P AGE and Western-blot. Cytopathic effects（CPE）were applied to examine the potency of recombination rChIFN-α-ChIL-18 against vesicular stomatitis virus（VSV）and newcastle disease virus（NDV）proliferation.【Result and conclusion】 The fusion gene of ChIFN-α-ChIL-18 was successfully constructed and cloned into pET-28a vector. The rChIFN-α-ChIL-18 protein was expressed in E. coli and successfully purified with a molecular mass of about 38 000 and more than 90% on SDS-PAGE，which indicated that the correct rChIFN-α-ChIL-18 fusion protein had been obtained.The antiviral activity units of rChIFN-α-ChIL-18 protein inhibiting the reproduction of VSV and NDV on chicken embryo fibroblast（CEF） cells were much higher than those of the recombinant rChIFN-α，rChIL-18 protein.