Objectives: Acute coronary syndrome (ACS) is an acute disease with high mortality. Although early percutaneous coronary intervention (PCI) is proved to be the practical approach in treating ACS, the incidence of cardiovascular events is still far from satisfactory. The combination of Suxiao Jiuxin Pill (SJP) and Western medicine is one conventional approach in the treatment of ACS. Many elementary and clinical trials have proved the efficacy and safety in the improvement of cardiocerebral vascular conditions. The aim of this project is to evaluate the safety and efficacy of SJP on ACS with early PCI patients. Trial Design: This is a multicenter randomized, double-blind placebo-controlled trial. Trial registration: ChiCTR-TRC-13003053. Settings: Hospitals. Subjects: A total of 200 ACS with early PCI patients were randomly divided into SJP group (n = 100) and placebo group (n = 100). Interventions: The SJP group was treated with routine treatment and SJP (taking eight SJP pills orally each time, three times per day). The placebo group was treated with routine treatment along with equal amounts of SJP placebo. The course of treatment was 6 months and a follow-up visit at 12 months. Outcome Measures: Assessments of major adverse cardiovascular events (MACE), safety assessments, adverse events, left ventricular systolic function (LVEF), Seattle angina questionnaire (SAQ), troponin C (cTNI), C-reactive protein (CRP), fibrinogen (Fib), and cystatin C (cysC). Results: The SJP group had a relatively low incidence of MACE than the placebo (p < 0.05, odds ratio: 1.916, 95% confidence interval [0.999-3.674]). LVEF was significantly higher in the SJP group than the placebo group on the 360-day follow-up (p < 0.01). SJP had a significant increase score in the SAQ subscale of physical limitation, angina frequency, and treatment satisfaction (p < 0.05). There is no significant difference in the cTNI and CRP level between the two groups. The serum concentration of Fib and cysC in the SJP was significantly decreased compared with the placebo (p < 0.05). The numbers of adverse events between the two groups were not statistically different (p > 0.05). Conclusions: SJP is associated with a reduction in MACE, and an improvement of heart function and quality of life in ACS patients with early PCI, and is probably safe to use.