Abstract： Objective： To observe the clinical effect of Kuanxiong aerosol on critical coronary artery lesions based on quantitative flow ratio(QFR). Methods： A total of 43 patients with unstable angina pectoris of coronary heart disease were selected and divided into the experiment group and the control group according to random number table method， 22 and 21 cases in each group respectively. The coronary angiography(CAG) images were firstly collected. The experiment group was continuously sprayed with Kuanxiong aerosol under the tongue， while the control group was sprayed with 0.9% sodium chloride solution under the tongue. After five minutes， the images were re- angiographed and collected. The QFR， the scores of Visual Analogue Scale(VAS) between the two groups and coronary blood flow velocity in the experiment group were compared before and after treatment. Results：After treatment，there was no significant difference in QFR between the two groups(P＞0.05). After treatment，the VAS score in the experiment group was decreased when compared with that before treatment(P＜0.05)， and was lower than that in the control group at the same period(P＜0.05). There was no significant difference in the VAS scores in the control group before and after treatment(P＞0.05). Eight patients in the experiment group were selected for the analysis of coronary blood flow velocity，of which five patients were improved when compared with that before treatment，and two patients were the same. There was significant difference in the comparison of the average blood flow velocity of the coronary artery before and after treatment in the experiment group(P＜0.05). Conclusion： Kuanxiong aerosol can effectively improve the immediate symptoms and coronary blood flow velocity of patients with angina pectoris，and has a certain effect on improving coronary microcirculation.