Aim To explore the predictive value of red cell distribution width (RDW) for contrast-induced nephropathy (CIN) in patients of type 2 diabetes with percutaneous coronary intervention (PCI). Methods A total of 310 ACS patients who received PCI treatment in the hospital from January of 2013 to December of 2015 were retrospectively studied in this project. These patients were divided into 2 groups by serum creatinine before and after surgery:Non-CIN group(n=275); CIN group(n=35), compared to the baseline condition at admission, the patients either had the serum level of creatinine raising up 25% or the serum level of creatinine increasing ≥ 0.5 g/L within 72 hours after PCI. Results The study found that under the same risk factors, compared with Non-CIN group, the RDW in the CIN group had increased, all P<0.05. Logistic analysis revealed RDW was the independent risk factor for CIN. Conclusion Elevated RDW has the predictive value for CIN occurrence in type 2 diabetes with PCI treatment.