Objective: This study aimed to explore the prognostic value of the chronicity score in patients with diabetic kidney disease (DKD) patients and compare it with the traditional DKD RPS pathological classification. Methods: The clinical data and pathological examination results of 129 patients, who were hospitalized in the First Affiliated Hospital of Nanjing Medical University and pathologically diagnosed with DKD by renal biopsy from January 2014 and September 2020,were retrospectively analyzed in this study. Based on the renal chronicity score, patients were divided into three groups: mild (n=34), moderate (n=50), and severe (n=45). The clinical characteristics and pathological indicators of each group were compared, and the results were evaluated against the DKD RPS pathological classification. Cox regression analysis was used to identify factors influencing poor renal outcomes, Kaplan-Meier survival curves were employed to compare cumulative renal event-free survival rates, and receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic value of the chronicity score alone and in combination with estimated glomerular filtration rate (eGFR) and 24-hour urinary protein in predicting renal outcomes. Results: Patients with higher chronic lesion scores exhibited worse renal function,more pronounced anemia, and a higher pathological grade according to the DKD RPS classification. The Kaplan-Meier survival analysis revealed that patients with higher chronic lesion scores had significantly lower cumulative survival rates without renal endpoint events, indicating poorer prognosis (P<0.05). Cox regression analysis identified a high chronic lesion score as an independent risk factor for renal endpoint events (P<0.05). The ROC curve analysis demonstrated that the diagnostic value of the chronic lesion score was slightly lower than that of the DKD RPS pathological grade (AUC=0.651 vs. 0.875), though no statistical difference was observed between the two. When combined with eGFR and 24-hour urinary protein, the AUC value of the chronic lesion score increased to 0.810.