Objective To analyze the polymorphism of GH gene in Tibet miniature pig and Guangxi Bama miniature pig by PCR-RFLP. Methods The polymorphism of the -119bp-+486 bp fragment (growth hormone gene) of 108 Tibet miniature pigs and 132 Guangxi Bama miniature pigs was detected by PCR-ApaI-RFLP and PCR-Hin6I-RFLP. Results (1) The PCR products were cut by ApaI, and produced two alleles:A (449 bp + 101 bp + 55 bp) and B (316 bp + 133 bp + 101 bp + 55 bp)。The frequency of allele A was higher than that of allele B. The frequency of the AA genotype was higher than that of the AB and BB genotypes. (2) The PCR products were cut by Hin6I, and produced four alleles:G1 (605 bp), G2 (498 bp+107 bp), G3 (449 bp+156 bp) and G4 (449 bp+107 bp+49 bp). The allele frequency of G4 was higher than that of G1, G2 and G3. The frequency of allele G1s was the lowest. Both Tibet miniature pig and Guangxi Bama miniature pig exhibited moderate polymorphism. The frequencies of G2G3, G2G4, G3G4 and G4G4 genotypes were higher than others. (3) There was no significant difference between the expressions of the allele in the Tibet miniature pig and Guangxi Bama miniature pig revealed by PCR-RFLPs. ConclusionsThe frequency of allele A of GH gene in Chinese miniature pig species, such as Tibet miniature pig and Guangxi Bama miniature pig, are rather high.