Abstract: In this experiment, polymorphism of 62nd SNP of Prepro-orexin gene in four porcine breeds (including Erhualian, xiang, huai and Jiangquhai pig) was anylised by PCR-RFLP method. The relationship between litter size and different genotype of Erhualian breed was analysized. The results showed that there are three genptypes in four porcine breeds, including AA, AB and BB. Frequencies of allele and genotype had a significant difference in differenf breeds. Erhualian and Xiang pigs had three genotypes, Jiangquhai pig had two genotypes, and Huai had only AA genotype. Litter size in populations with differenf genotypes had no significant difference within Erhualian pig, which showed that polymorphism of 62nd SNP of Prepro-orexin gene had no effect on litter size.