Aim To investigate the value of serum CD147 level in evaluating the prognosis of non-infarction related artery (non-IRA) after percutaneous coronary intervention (PCI). Methods 103 patients with ST-segment elevation myocardial infarction (STEMI) complicated with multi-vessel disease admitted to our hospital from March 2017 to March 2019 were selected. All patients were treated with non-IRA PCI 3~7 days after PCI successfully opened IRA. According to whether major adverse cardiovascular event (MACE) occurred 6 months after operation, the patients were divided into two groups:non-MACE group (n＝75) and MACE group (n＝28). According to Killip cardiac function classification standard, the patients were graded. Echocardiography and left ventricular ejection fraction (LVEF) were recorded. Coronary angiography was performed by Judkins method and the stenosis was recorded. The differences of general information and serum biochemical indexes were compared between the two groups. ROC curve was drawn to evaluate the diagnostic value of serum CD147 level for MACE after multi-vessel PCI in STEMI patients. COX regression model was used to analyze the risk factors of MACE after multi-vessel PCI in STEMI patients. Results Compared with non-MACE group, the proportion of hyperlipidemia, Killip Ⅱ~Ⅲ ratio, low density lipoprotein cholesterol and CD147 levels were higher in MACE group (P＜0.05), and LVEF was lower (P＜0.05). ROC results showed that the area under curve of serum CD147 in diagnosing MACE after multi-vessel PCI in STEMI patients was 0.834, the cut-off value was 625.58 ng/L, the corresponding sensitivity and specificity were 78.60% and 81.30% respectively, and the Youden index was 0.599. COX regression model showed that Killip Ⅱ~Ⅲ, LVEF＜45% and high level CD147 were independent risk factors for MACE after multi-vessel PCI in STEMI patients (P＜0.05). Conclusions CD147 is closely related to the prognosis of STEMI patients undergoing multi-vessel PCI. It has a certain diagnostic value for MACE after PCI in STEMI patients, and can provide a reference for the prognosis evaluation of STEMI patients undergoing multi-vessel PCI.