Abstract: By the PCR-RFLP method, the polymorphisms of exon 14 of Mx1 gene were detected in wild boar and 16 native and exotic pig breeds, with the analysis of restrictive enzyme Hin6Ⅰdigestion, there were 6 genotypes and 3 alleles. The exotic pig breeds and Songliao Black pigs appeared AA, AC and CC genotypes, all other Chinese native pig breeds appeared AA, BB and AB genotypes, the Sutai pigs appeared all six kinds of genotypes. Among all pig breeds in this study, the allele B only appeared in Chinese native pig breeds, while the allele C only appeared in exotic pig breeds and developed pig breeds which originated from exotic pig breeds. Dendrogram of phylogenetic relationships among these pig breeds based on polymorphism of Mx1 gene also showed that genotype distribution in Mx1 exon 14 was obviously different between Chinese native pig breeds and exotic pig breeds, all exotic pig breeds and two developed pig breeds formed one cluster, wild boar and all Chinese native pig breeds were clustered in the other large population, among this population, Fengjing pig, Erhualian pig and Meishan pig formed one branch firstly, and it had the nearest genetic relationship with wild boar. The frequency of AB genotype was relative higher in the individuals of wild boar and Tibetan pig, which were 0.515 and 0.302, respectively. The frequency of AB genotype in the populations of Fengjing pig, Erhualian pig and Meishan pig ranged from 0.348 to 0.591. All these results indicated that the individuals with AB genotype maybe have stronger ability of virus-resistance, and the Taihu pigs (Fengjing pig, Erhualian pig and Meishan pig) were perhaps the good potential materials for virus-resistant breeding in the future.