Aim To evaluate the possible association between PPARγ2 gene Pro12Ala polymorphism and type 2 diabetes mellitus in a population-based study in Weifang Han population. Methods Genomic DNA was extracted from peripheral blood leucocytes of 170 patients with type 2 diabetes mellitus and 54 normal subjects. The Prol2Ala polymorphism was screened using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results The frequencies of Pro allele and Ala allele were 0.9487 and 0.0513 respectively in 224 subjects from Han people of Weifang Chinese. The Ala allele frequency in the control group and type 2 diabetes mellitus group were 0.093 and 0.041 respectively. The Ala allele frequency in type 2 diabetes mellitus was significantly lower than that in the control group (P=0.039). Conclusion PPARγ2 gene Prol2Ala polymorphism is associated with the incidence of type 2 diabetes mellitus in Han people of Weifang Chinese. The Ala allele confers modest protection against the onset of type 2 diabetes mellitus.