The PCR–SSCP and PCR–RFLP in exon 4, exon 5, exon 6 and intron 3 of POU1F1 gene and their correlations with growth traits were investigated in Hainan WZS pig in a closed breeding colony and their inbred line and in Hainan black pigs (Lingao pig and Tunchang pig). The results showed there were two alleles and three genotypes in exon 4 and intron 3 of POU1F1 gene and there were no polymorphism in exon 5 and exon 6. They were Hardy–Weinberg equilibrium state in exon 4 of POU1F1 gene in WZS pig, Lingao pig and Tunchang pig, while WZS pig inbred line showed unequilibrium state, and the four breeds all had intermediate genetic polymorphism (0.250.50). The least square analysis showed that the different genotype of exon 4 and intron 3 of POUlF1 gene did not affect body weight of 2, 8 and 12monthold pigs (P>0.05).