In the study, the Mx gene promoter, exon 1, exon 2, and exon 14 and intron 13 in eight Chinese local chicken breeds were examined. Amino acid 631 in the GED region was tested in eight Chinese local chicken breeds and two exotic breeds. The frequency of allele A was 0.1259 and the frequency of allele G was 0.8741. Meanwhile, induction of expression of the Mx gene in chicken embryo fibroblasts was analyzed in the local chicken breed, Beijing-you and the exotic breed, White Leghorn.The semi-quantitative and quantitative results showed that the expression of the Mx gene in White Leghorn was significantly different under different induction conditions. There was also a difference in the genotypic distribution of S631N in two breeds: allele A/G was 0.8471/0.1529 and 0.1613/0.8387 in White Leghorn and Beijing-you chickens, respectively. We speculate that the difference in the genotypic distribution has an effect on Mx gene expression.