Objective: Explore the biomarkers related to proliferative diabetic retinopathy by analyzing the protein expression profile changes of plasma exosomes in patients with difference phases of diabetic retinopathy, and investigate potential molecular mechanisms and therapeutic targets. Methods: Enrich exosomes from plasma by column extraction method. NTA, WB and TEM were used to characterize the obtained exosomes, and exosome proteinomics was performed by chromatography⁃mass spectrometry. Corhorts: The study was divided into four groups: a healthy control group, a diabetic without diabetic retinopathy group, a non-proliferative diabetic retinopathy group, and a proliferative diabetic retinopathy group, with 6 cases in each group.