Background <p>Diabetic retinopathy (DR) is one of the common ocular complications of diabetes. Recent studies have also found that miR-455-3p is dysregulated in DR. However, its underlying mechanisms warrant further investigation.</p> Objective <p>This study focused on the clinical value of miR-455-3p and its regulatory mechanisms in DR.</p> Materials and methods <p>This study recruited 130 patients with DR and 105 healthy individuals. HRMECs treated with high glucose were used to simulate DR conditions. The expression of miR-455-3p and Integrin beta 1(<i>ITGB1</i>) were assessed by qRT-PCR while the target relationship between them was validated via Dual-luciferase reporter assay. ROC curve was utilized for the diagnostic performance. CCK-8 and flow cytometry were employed for proliferation and apoptosis measurement while ELISA was used for inflammation.</p> Results <p>Serum miR-455-3p was found to be distinctly downregulated in patients with DR. The expression of serum miR-455-3p was negatively associated with HbA1c levels in patients with DR. The miR-455-3p also exhibited strong diagnostic potential for distinguishing patients with DR from healthy individuals. In high glucose-induced HRMECs, miR-455-3p was significantly downregulated. miR-455-3p can target and negatively regulate <i>ITGB1</i>, thereby inhibiting the proliferation and inflammation of HRMECs induced by high glucose and promoting cell apoptosis.</p> Conclusion <p>Decreased miR-455-3p promotes diabetic retinopathy progression via negative regulation on <i>ITGB1</i>.</p> Clinical trial number <p>Not applicable.</p>