The angiotensin-converting enzyme (ACE) gene is one of the most studied candidate genes related to diabetic retinopathy (DR). ACE 2350 G/A polymorphism (rs4343) is known among the polymorphisms of this gene to have the most significant effect on plasma ACE concentrations. The aim of the present study was to investigate the relationship between 2350 G/A polymorphism of ACE gene and the susceptibility of DR in Chinese Han population. A case-control study for 145 type 2 diabetes mellitus (DM) patients, including 63 type 2 DM without DR (NDR) and 82 type 2 DM with DR (DR), and 90 subjects of age, gender matched normal controls (NC group) was performed. ACE 2350 G/A genotypes were identified by polymerase chain reaction and restriction digestion in all study participants. The distribution of the ACE 2350 G/A genotypes (GG, GA, and AA) was 35.56, 45.55, and 18.89 % in the NC group, 28.57, 46.03, and 25.40 % in the NDR group, and 15.85, 46.34, and 37.81 % in the DR group, respectively. There were no significant differences in either genotype frequency distribution (P = 0.5266) or allele frequency distribution (P = 0.2425) between the NC group and NDR group. However, the distribution of genotype frequency (P = 0.0026) and allele frequency (P = 0.0003) in the DR group showed a significant difference when compared to that of NC group (P = 0.0075). Moreover, there was statistical difference in allele frequency distribution (P = 0.0328) between the DR group and the NDR group. No statistical differences were observed between ACE 2350 G/A polymorphism and the diabetes duration or types of DR. Results obtained in this study indicate that ACE 2350 G/A polymorphism is associated with DR in Han Chinese patients with type 2 DM.