Abstract： Objective To investigate the effects of uncoupling protein 2 (UCP-2) gene a 45 bp insertion/deletion (Ins/Del) polymorphism in the 3'-untranslated (3'-UTR) of its exon 8 on macroangiopathy in diabetes mellitus.Methods A total of 182 patients were selected,80 cases with macroangiopathy( A group), 102 cases without macroangiopathy(B group) ,UCP-2 gene polymorphism was confirmed by electrophoresis after PCR with 3% agarose,then compared genotype and allele gene frequency. Results The 3'-UTR Ins/Del polymorphism of UCP-2 gene in A group ( II:6. 25% 、ID: 18. 75% 、DD:75.00% ) and B group( II:9. 80% 、ID:23.53%、 DD: 66. 67% ) had no significant difference ( P ＞ 0. 05 ), and there was also no difference of alleles frequencies in two groups ( I: 15.63 %、 D: 84. 37 % )and(I:21.57% 、D:78.43%)(P ＞0.05). Conclusion No relationship of the 3'-UTR a 45bp Ina/Del polymorphism in exon 8 of the UCP-2 gene was found with macroangiopathy in diabetes mellitus.