Acute ST-segment elevation myocardial infarction (STEMI) is a common manifestation of cardiovascular emergencies. Percutaneous coronary intervention (PCI) and guideline-recommended pharmacotherapy have reduced mortality rates associated with STEMI, but the incidence of recurrent ischemic events, particularly early ischemic events, remains high. Current research suggests that low-density lipoprotein cholesterol (LDL-C) levels not meeting guideline-recommended levels and inflammation are closely related to early recurrent ischemic events. Evolocumab, a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor, rapidly and effectively reduces LDL-C levels and suppresses inflammation. Long-term use in patients with acute coronary syndromes can reverse atherosclerosis and improve prognosis. However, data on its use in STEMI patients are limited, particularly regarding the cardioprotective effects of preoperative administration of 420mg evolocumab subcutaneous injection. This study aims to evaluate the effects of administering evolocumab 420mg before emergency PCI on lipid profiles, inflammatory markers, myocardial injury, and short-term prognosis in STEMI patients through a single-center, randomized, open-label study. It aims to provide theoretical evidence for further reducing the risk of recurrent cardiovascular events in STEMI and identifying more optimized treatment strategies.