The objective of this study was to evaluate the clinical efficacy and safety of nitroprusside injection for preventing the slow-flow/no-reflow phenomenon after percutaneous coronary intervention (PCI). We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2011), PubMed, EMbase, and Google Scholar for data. Two reviewers independently evaluated the quality of the included studies and extracted the data. A meta-analysis was performed using RevMan 5.0 software. Four randomized controlled trials (RCTs) involving 319 patients were included. The results of the meta-analyses showed that intracoronary nitroprusside is beneficial in preventing no-reflow/slow-flow, in reducing corrected TIMI frame count, and in improving left ventricular ejection fraction. It also likely reduces adverse reactions in patients after PCI and rehospitalization due to cardiovascular events. However, we must caution that in this review, there is a moderate possibility of bias with regard to patient selection, performance, and publication because of the small number of included studies. A larger sample size and high-quality RCTs are needed for a more reassuring analysis.