Background: The morbidity of myocardial infarction is keeping raise in this decade. Because of high safety and operability , percutaneous coronary intervention(PCI) has been used to conquer this disease for more than 20 years.An important complication of PCI is contrast induced nephropathy(CIN), which raises our attention. Previously, we started a study to explore the correlation between acute kidney injury and myonecrosis after scheduled percutaneous coronary intervention. Our study showed that the rate of CI-AKI in patients with post-procedural myocardial injury and undergoing elective PCI was higher than that in patients free of injury. Methods: In this study,forty male rats were randomly divided into four groups: control group (n=8), CM group (n=12), AMI group (n=8) and AMI+CM group (n=12), then velocity of renal artery blood flow (VRABF), computer tomography (CT), serum creatinine(Scr), reactive oxidative species (ROS), periodic acid-Schiff (PAS) and TUNEL were used to estimate the injury of kidney. We analyzed 327 non-ST-segment elevation acute coronary syndrome subjects undertaking elective PCI. Serum levels of creatinine (SCr) and the eGFR before coronary angiography, and 24–72 h after contrast administration were recorded to assess the renal function. Results: The data showed that VRABF was lower in AMI+CM group than CM group from 0 minute to 24h and CT number in cortex was higher in AMI+CM group than CM group at 4-hour. As well as the level of Scr in AMI+CM group displayed a significantly increase at 24-hour compared with CM group. The histopathologic scores and percentage of tubular cell apoptosis were higher in AMI+CM group at 24-hour. In 327 patients, we found that CI-AKI occurred more often in subjects with post-procedural myonecrosis (PMN) than in those without PMN (20.8% versus 5.8%, respectively, P=0.001). Conclusion: Compared to the elective patient, the injury of CIN exhibited a higher severity in AMI patient.