Abstract： Objective To investigatethe value of advanced oxidation protein products (AOPP ) in predicting in-stent restenosis in patients with coronary heart disease and diabetes mellitus undergoing percutaneous coronary intervention(PCI) . Methods A total of 682patients with coronary heart disease and diabetes mellitus undergoing coronary angiography (CAG) and PCI were enrolled in this prospective cohort study .All the subjects were divided into two groups :low level of AOPP group (AOPP ≤50.51μmol/L ,n=350) and high level of AOPP group (AOPP>50.51μmol/L ,n=332) according to the average level of AOPP .Therate of In-stent restenosis (ISR)was evaluated after1-year follow-up . Results The rate of ISR was higher in high level AOPP group than in low level AOPP group (10.24％ vs 5.14％ ,P<0.05) .Logistic regression analysis showed that AOPP>50.51 μmol/L was an independent risk factor for ISR prediction (OR 1.842 ,95％ CI 1.568～1.999 ,P<0.05) . Conclusion AOPP may be a biomarker for predicting ISR in patients with coronary heart disease and diabetes mellitus undergoing PCI .