Objective:To observe the effects of Wushen Oral Liquid combined with conventional Western medicine therapy on autonomic nervous function in patients after percutaneous coronary intervention (PCI) for myocardial infarction (MI) of the qi-yin deficiency type. Methods70 patients after PCI for MI of the qi-yin deficiency type were randomly assigned into treatment group and control group, 35 patients in each group. Conventional Western medicine therapy was given to the control group and its combination with Wushen Oral Liquid was administered to the treatment group. The treatment course was 3 months in both groups. Therapeutic effect on TCM syndromes was observed and changes in measures of autonomic nervous function (variability and deceleration capacity of heart rate) were compared.  Results:①The overall effective rate was 97.1% and 88.6% in the treatment and control groups respectively. The therapeutic effect on TCM syndromes in the treatment group was significantly superior to that in the control group (P<0.05). ②The levels of SDNN, SDANN, rMMSD and PNN50 increased significantly in the treatment group (P<0.05) and the levels of SDNN and rMMSD increased significantly in the control group (P<0.05) after treatment compared to those before treatment. The levels of SDNN, SDANN and rMMSD were significantly higher in the treatment group than in the control group after treatment (P<0.05). ③The deceleration capacity of heart rate increased significantly in both groups after treatment compared to that before treatment (P<0.05). There was no significant difference in deceleration capacity of heart rate between the groups after treatment (P>0.05).  Conclusion:Wushen Oral Liquid in combination with conventional Western medicine therapy improves the TCM syndrome of patients after PCI for MI of the qi-yin deficiency type, and balances the autonomic nervous function by increasing the measures for heart rate variability (SDNN, SDANN and rMMSD) and tending to elevate the deceleration capacity of heart rate.