To observe the effect of Shenyuan Yiqi Huoxue capsule on ACE2 of patients with unstable angina(UA) of Qi-deficiency and Blood-stagnation syndrome after PCI in preoperative period,and explore its potential.Methods:Conduct RCTs in perspective with placebo to observe the ACE2,ERK,PKC level in the serum of patients with UA,thus studying the clinical effect of Shenyuan Yiqi Huoxue capsule.Results:Before the treatment,no statistical significance were found between the two groups in ACE2,ERK,PKC(P>0.05).While after the treatment there are significant difference in all those three levels in the treatment group and between the two groups(P<0.05).There being a rise of levels of all three in the control group after the surgery signifies myocardial damage.However,the occurrence of angina decreased in both groups after treatment,implying effectiveness; only without statistically higher total effective rate of the treatment group (P>0.05).Conclusion:Shenyuan Yiqi Huoxue capsule has effect on myocardial damage after PCI.