Post-contrast acute kidney injury (PC-AKI) has emerged as the third leading cause of iatrogenic acute renal failure. Diabetes mellitus not only represents an independent risk factor for PC-AKI but also remains a major cause of chronic kidney disease (CKD). SS-31, an antioxidant peptide targeting mitochondria, is a potential preventive drug for PC-AKI. In this study, we established a PC-AKI model by injecting iodixanol in type 1 diabetic mice. Blood and tissue samples were collected to confirm that iodine injection caused excessive reactive oxygen species (ROS) in the kidney, activated the NLRP3 inflammasome pathway, and subsequently aggravated the development of PC-AKI. We also confirmed that SS-31 can reduce acute kidney injury induced by iodine contrast agent in diabetes by protecting mitochondrial function and inhibiting the ROS-NLRP3 signaling pathway.