Optimizing the metabolism of the myocardium is a new strategy for patients with ischemic heart disease. Many studies have reported beneficial effects of trimetazidine (TMZ) on the clinical prognosis of patients with ischemic heart disease, but whether these beneficial effects are extended to patients undergoing percutaneous coronary intervention (PCI) remains uncertain. A meta-analysis was performed to evaluate the effect of TMZ on patients undergoing PCI. We conducted an electronic search of PubMed, Cochrane databases, the China National Knowledge Infrastructure, and Chinese Biological Medicine Database to identify randomized controlled trials. Methodological quality was assessed according to the Jadad scale score, and the meta-analysis was performed using Cochrane Collaboration RevMan 5.2 and Comprehensive Meta-Analysis. Dichotomous data were analyzed using relative risk (RR) or odds ratio (OR) with effect size indicated by the 95% confidence interval (CI), and continuous variables were analyzed using weighted mean differences (WMD) with effect size indicated by the 95% CI. Sensitivity analysis was performed by changing the statistical methods and effect model. Nine studies involving a total of 778 patients were included in this meta-analysis. Additional use of TMZ significantly improved the left ventricular ejection fraction (WMD: 3.11, 95% CI: [2.26, 3.96]) and reduced elevated cardiac troponin Ic level (RR: 0.69, 95% CI: [0.48, 0.99]), angina attacks during PCI (OR: 0.16, 95% CI: [0.07, 0.38]), and ischemic ST-T changes on the echocardiogram during PCI (RR: 0.76, 95% CI: [0.59, 0.98]). However, no significant difference was observed in serum BNP level 30 days after PCI between the experimental and control group. Additional use of TMZ for patients undergoing PCI may reduce myocardial injury during the procedure and improve cardiac function.