Objective: To evaluate the correlation between new inflammatory factor interleukin-17 (IL-17) and diabetic retinopathy (DR). Methods: In this case control study, patients (n=625) with type 2 diabetes were divided into a DR group (n=251, 40.2%) and a non-diabetic retinopathy (NDR) group (n=374, 59.8%). The general information and biochemical indexes were compared between the two groups. Comparison between groups using t/χ2 square test, and the risk factors of DR were analyzed by multiple logistic regression.Results: Compared with the NDR group, the age (t=3.012), duration of diabetes (t=3.873), arteriosclerosis rate (x2=23.791), fasting blood-glucose (t=2.659), albumin/creatinine (A/C) (t=5.917), and serum IL-17 level (t=5.242) of the DR group were significantly increased (P<0.05). The sex, body mass index (BMI),hypertension, smoking, diastolic blood pressure, systolic blood pressure, glycosylated hemoglobin, total cholesterol, triglyceride, and high-density lipoprotein of the two groups were not significantly different from one another. Logistic regression analysis showed that the duration of diabetes (OR=1.120, P=0.003),A/C value (OR=1.014, P=0.028), and IL-17 (OR=0.854, P=0.002) were risk factors of DR. Conclusions:IL-17 is closely related to DR, and the level of serum IL-17 can provide significant guidance with respect to the clinical diagnosis and treatment of this disease.