Abstract: Objective To investigate the correlation between TNF-β NcoⅠpolymorphism and PDR.Methods PCR-RFLP analysis of frequencies of allele in each group.Results The frequency of allele TNF-β2 was significantly higher in patients with PDR than that without PDR(P<0.05).Conclusion This polymorphism of TNF-β can be served as a susceptible genetic marker of PDR.