Objective To investigate the effect of different waiting times of elective percutaneous coronary intervention (PCI) for non-infarct related artery (Non-IRA) on the prognosis in patients with ST segment elevation myocardial infarction (STEMI). MethodsA retrospective study was carried out on 160 STEMI patients with multivessel disease hospitalized in our department from August 2015 to December 2016. They were 105 males and 55 females, at an age of(63.1±9.6)years. According the waiting times for elective PCI, they were assigned into ≤14 d group (n=92) and 30-60 d group (n=68). The results of coronary angiography, numbers of Non-IRA stent implantation and the main complications during hospitalization were compared. The patients were followed up for 6 months. The incidence of major adverse cardiovascular events (MACEs) were compared between the 2 groups in 1 and 6 months after PCI. The differences between the groups were compared by Student’s t test and Chi-square test for different data types. ResultsThere was no significant difference in the implanted stent number between the ≤14 d group and 30-60 d group (P>0.05). The incidence of PCI related complications during hospitalization was obvious higher in the ≤14 d group than the 30-60 d group (18.5% vs 7.4%; P=0.43). There was no obvious difference in the incidence of MACEs in 1 month after PCI between the 2 groups, but the incidence was notably lower in the 30-60 d group in 6 months (5.9% vs 16.3%;P=0.042). Conclusion Waiting time of 30-60 d reduces the risks for PCI-related complications during hospitalization and for MACEs in 6 months after PCI, and which might be an optional time for elective PCI in treatment of Non-IRA.