Objective:To investigate the clinical efficacy of Danhong injection treatment of coronary slow flow phenomenon (CSFP),and to explore the possible mechanism of Danhong inj ection to improve coronary microcirculation.Meth-od:Coronary angiography of coronary slow flow phenomenon and found that 64 patients with positive exercise stress test were randomly divided into observation group (n=32)and control group (n=32),patiens in control group were given conventional treatment,while those in observation group were given Danhong inj ection on the basis of conventional treatment.All patients were treated for 10 days,before and after treatment the changes in clinical effi-cacy and measurement of blood endothelin-1(ET-1),thrombomodulin (TM)and c-reactive protein (hs-CRP)levels were observed.Results:Before treatment,all the observation indexes were no statistically significant difference be-tween the two groups (P>0.05).After treatment for 10 days,the two groups were compared with the observation group improvement of angina extent and ECG and exercise stress test parameters were better than the control group, the differences were statistically significant (P<0.05).Serum ET-1,TM,hs-CRP levels compared with the observa-tion group significantly lower in the control group,the differences were statistically significant (P<0.01).Conclusion:Danhong inj ection can improve blood flow in patients with coronary slow clinical symptoms,improve vascular endothelial function disorder and reduce the degree of inflammation.