Objective  To study the application value of quantitative urine albumin/creatinine ratio (ACR) detection in the early screening of diabetic nephropathy (DKD).Methods  A total of 128 patients with early DKD and 128 healthy subjects admitted to the hospital from January 2021 to January 2022 were retrospectively selected and divided into the study group and the control group, respectively. The morning urine ACR and blood serum urea nitrogen (BUN), serum creatinine (Scr), amyloid A(AA), cystatin C(Cys C) levels were compared between the two groups, and Pearson test was used to evaluate the correlation between urinary ACR and AA, Cys C. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of ACR for DKD.Results  The levels of urinary ACR and serum BUN, Scr, AA, Cys C in the study group were (39.68±5.25) mg/g, (4.13±0.81) mmol/L, (65.52±10.18) μmol/L, (4.21±0.68) mg/L, (1.01±0.13) mg/L, respectively.In the control group, the levels of urinary ACR and serum BUN, Scr, AA, Cys C were (10.98±1.91) mg/g, (4.29±0.88) mmol/L, (68.05±12.46) μmol/L, (14.86±2.57) mg/L, (1.82±0.34) mg/L, respectively. The urinary ACR, serum AA and Cys C levels of the study group were significantly higher than those of the control group, and the differences were statistically significant (all P<0.05). There were no statistically significant differences in serum BUN and Scr levels between the two groups (all P>0.05). Urine ACR was positively correlated with serum AA and Cys C levels (r=0.311，0.415，all P<0.05). ROC curve analysis showed that with 30.00 mg/g as the cut-off value, the area under the curve of ACR for the diagnosis of DKD was 0.934 (95%CI：0.902～0.995), the sensitivity was 85.37%, and the specificity was 90.19%.Conclusions  Urinary ACR has a significant effect in the early screening of DKD, and it can be used as an auxiliary diagnostic index for early DKD.