Abstract: Objective To investigate the value of urinary albumin-to-creatinine ratio(ACR), β₂ microglobulin(β₂-MG)and retinol binding protein(RBP)in early diagnosis of renal damage in diabetic patients. Methods A total of 96 patients with diabetes who were treated in our hospital were selected as research objects, and were divided into diabetic nephropathy group(n=49)and diabetes group(n=47)according to the qualitative test results of urinary protein. Another 50 healthy patients who underwent physical examination in the outpatient department during the same period were selected as healthy group. The levels of ACR, β₂-MG and RBP were detected and compared in three groups, and sensitivity, specificity and accuracy of detection of ACR, β₂-MG or RBP alone and their combination were calculated. Results The levels of urinary ACR, β₂-MG and RBP in the diabetic nephropathy group were significantly higher than those in diabetes group and healthy group(P<0.05). The positive rates of detection of ACR, β₂-MG or RBP alone and their combination in the diabetic nephropathy group were significantly higher than that in the diabetes group(P<0.05). The sensitivity, specificity and accuracy of combined detection of urinary ACR, β₂-MG and RBP in diagnosis of diabetic nephropathy were 95.92%, 85.57% and 89.04%, respectively, and there were significant differences in sensitivity and accuracy between single detection and combined detection(P<0.05), but no significant difference was found in specificity(P>0.05). Conclusion Urinary ACR, β₂-MG and RBP levels can reflect early renal injury degree in diabetic patients, and combined detection has better - sensitivity and accuracy in diagnosis of diabetic nephropathy.