OBJECTIVE To investigate the effects of alirocumab combined with atorvastatin on clinical efficacy and safety of patients with acute coronary syndrome （ACS） who underwent percutaneous coronary intervention （PCI）. METHODS A total of 207 patients with ACS who underwent PCI in our hospital from January 2021 to December 2023 were randomly divided into alirocumab group， ezetimibe group and control group， with 69 cases in each group. All patients received routine thrombosis prevention and antihypertensive treatment after PCI. On this basis， patients in the control group were treated with atorvastatin （20 mg/time， once a day）； patients in the ezetimibe group were treated with ezetimibe （10 mg/time， once a day） + atorvastatin （20 mg/time， once a day）； patients in the alirocumab group were treated with alirocumab （75 mg/time， once every 2 weeks） + atorvastatin （20 mg/time， once a day）. All patients in the three groups were treated for 8 weeks and followed up for another 6 months after treatment. The levels of cardiac function and lipid metabolism indices before and after treatment， as well as the occurrence of major adverse cardiovascular event （MACE） and other adverse drug reaction （ADR） during the follow-up period were compared among the three groups. RESULTS After treatment for 8 weeks， the levels of cardiac function and lipid metabolism indices in the three groups were significantly improved compared with those before treatment （P＜0.05）. Compared with the control group and ezetimibe group， the left ventricular ejection fraction in the alirocumab group was significantly increased， and the left ventricular end-diastolic diameter （LVEDD） was significantly shortened （P＜0.05）. Compared with control group， LVEDD of ezetimibe group was significantly shortened （P＜0.05）， the levels of total cholesterol， triglyceride and low-density lipoprotein cholesterol in the alirocumab group and ezetimibe group were significantly decreased （P＜0.05）. During the follow-up period， there was no significant difference in the total incidence of MACE and the total incidence of other ADR such as headache and abdominal pain among the three groups （P＞0.05）. CONCLUSIONS Alirocumab combined with atorvastatin can significantly improve cardiac function and regulate lipid metabolism indices in patients with ACS after PCI without increasing the risk of MACE or other ADR.