Objective To determine the effect of Compound Danshen Dripping pills on hemorrheology in acute coronary syndrome (ACS) patients before and after percutaneous coronary intervention (PCI) in order to investigate the clinical value of the pills on treatment of the disease. Methods A total of 90 patients with confirmed ACS undergoing PCI in our department from January 2011 to December 2013 were recruited in this study. Before treatment, they were randomly divided into 3 groups, that is, group A, group B, and group C, with 30 cases in each group. The patients of group A took 10 pills, 3 times per day besides conventional medication after PCI. Those of group B were given 20 pills followed by PCI surgery and took 10 pills, 3 times per day besides conventional medicine (the same as group A) after PCI. The patients of group C were treated with conventional therapy after PCI. Hemorrheological parameters were measured before and in 3 months after surgery. Results Compared with the parameters before treatment, whole blood viscosity at low and high shear rates were significantly lower in the 3 groups (P＜0.05), more significant changes were found in group A and B when compared with group C (P＜0.05). In addition, group A and group B had significant differences in erythrocyte aggregation rate and fibrinogen level compared with group C (P＜0.05). However, plasma viscosity was decreased in the 3 groups after treatment, but the difference was not statistically significant. Conclusion Compound Danshen Dripping pills combined with conventional medication significantly improve the hemodynamic parameters in ACS patients after PCI.