Objective: To explore the applications of optical coherence tomography angiography (OCTA) in diabetic retinopathy. Methods: A total of 63 diabetic patients in the Department of Ophthalmology, Seventh Affiliated Hospital of Sun Yat-sen University in 2021 were divided into 4 groups: the patients without diabetic retinopathy (T0, n=21), mild non-proliferative diabetic retinopathy (T1, n=21), moderate-to-severe non-proliferative diabetic retinopathy (T2, n=14) and proliferative diabetic retinopathy (T3, n=7). Biochemical Indicators were collected in all patients, such as fasting plasma glucose (FPG), glycated hemoglobin A1c (HbA1c), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), the blood urea nitrogen (BUN), creatinine (CRE) and the ratio of blood urea nitrogen and creatinine (BUN/CRE). The Macular Cube 521×128, Angiography3×3, and Angiography6×6 models of OCTA were used to obtain central retinal thickness (CRT), vascular density (VD) and perfusion density (PD) of each group. The data of all subjects was applied to do one-way ANOVA. Results: Prolonged duration of diabetes in T2 and T3 compared to T0 and in T3 compared to T1. Elevated BUN in T3 compared to all other groups. When T1, T2 and T3 were compared to T0, and T3 was compared to T1, the VD of the 6 mm ×6 mm outer layer decreased. Reduced VD of intact 6 mm ×6 mm region in T1, T2 and T3 compared to T0. Declining PD of the 6 mm ×6 mm outer layer in T2 and T3 compared to T0. Diminished PD of whole 6 mm ×6 mm area at T3 compared to T0. The VD of 3 mm ×3 mm inner layer was significantly reduced in T3 compared to T0 and T1. The VD of 3 mm ×3 mm intact area gradually dwindled in T3 compared with T0 and T1 (P<0.05). Conclusion: With the progression of diabetic retinopathy, the levels of BUN and CRE gradually increased, and the OCTA-derived vascular density and perfusion density gradually decrease. Vascular density may be more sensitive for early diabetic retinopathy screening than perfusion density.The use of the Angiography6×6 model may result in an earlier detection of changes in retinal blood flow in diabetic retinopathy.