All exons in progesterone receptor(pgr) gene in Xiaomeishan, Fengjing and Large White pig populations were screened using mixed genome DNA pool and direct sequencing methods. The results showed that only one site exhibits nucleotide polymorphism (SNP), which is in exon1 of pig pgr gene at 1 319 bp with base mutation from C to T (C1319T). This mutation do not cause the change of amino acid residue, which is a synonymous mutation. Based on this mutation, mismatched PCRRFLP method was established to analyze polymorphism of pgr gene in the above mentioned pig populations. According to PCR-RFLP, three pig populations is divided into AA, AB and BB genotypic types, in which AB types exist in Xiaomeishan and Fengjing pig populations, and BB, AB types in Large White pig population.