Aim To investigate the effects of different timing of arranged secondary percutaneous coronary intervention (PCI) for non-infarct related artery (non-IRA) on left ventricular function and prognosis in acute myocardial infarction (AMI) patients with coronary artery multivessel disease. Methods From January 2013 to December 7,6 AMI patients were admitted to the Department of Cardiology, Affiliated Hospital of Jiangsu University, who were confirmed by selective coronary angiography to have coronary artery multivessel disease and underwent planned secondary PCI.Of these patients, 218 were in the ST-segment elevation myocardial infarction (STEMI) group and 168 in the non-ST-segment elevation myocardial infarction (NSTEMI) group. Randomly choosing different time to perform secondary PCI on non-IRA, each group was divided into three subgroups according to the time interval (T) between two PCI operations:A group:3 days ≤ T ＜7 days; B group:7 days ≤ T ≤ 10 days; C group:T ＞ 10 days. The long-term and medium-term prognosis of the patients who underwent planned secondary PCI at different time were observed and compared, including left ventricular function, major adverse cardiovascular event (MACE) and survival rate. Results (1)218 patients with STEMI were followed up for an average of (42.54±15.60) months. The increased value of left ventricular ejection fraction (ΔLVEF) in A group,Bü group and C group was 2.91%±0.79%, 0.30%±0.58% and －0.12%±1.93%, respectively; The difference was statistically significant (P＝0.026). The total cumulative event-free survival rate of three subgroups were 90.0%, 67.2% and 41.2%, respectively, and the difference was statistically significant (P＜0.01). Survival rate after secondary PCI in A group was higher than that in B group and C group (P＝0.021, P＝0.010). (2)168 patients with NSTEMI were followed up for an average of (39.85±16.19) months. The ΔLVEF of A group,Bü group and C group were 1.73%±0.50%, 0.10%±0.71% and －1.57% ± 2.00%, respectively; The difference was statistically significant (P＝0.039). The total cumulative event-free survival rate of three subgroups were 87.0%, 59.7% and 28.6%, respectively, and the difference was statistically significant (P＜0.01). Survival rate after secondary PCI in A group was higher than that in B group and C group (P＝0.032, P＝0.012). Conclusion Timing of secondary PCI for non-IRA may affect left ventricular function and cumulative event-free survival rate in AMI patients with multivessel disease.