Abstract: Objective To investigate the relationship between Insulin Receptor Gene Exon 8 NsiI Polymorphism and type 2 diabetes mellitus Methods A cross-sectional survey was conducted among Han residents living in 6 counties, Sichuan province. Questionnaire survey, anthropometric measurement and blood test were carried out. We selected type 2 diabetes cases as case group(n=162) and healthy control individuals as control group(n=162) with frequency matching(1:1) of sex and age. Polymerase chain reaction and restriction fragment length polymorphism （PCR–RFLP）were adopted to examine the individual genotype. Results There were no significant differences in the genotype and gene frequency between cases and controls. Conclusion NsiI polymorphisms may be not associated with the type 2 diabetes in Han people of Liangshan ,Sichuan province

Key words: Type 2 diabetes, Gene polymorphism, Insulin receptor