Abstract：Objective：To observe the clinical effect of modified Zhigancao tang combined with metoprolol tartrate tablets for coronary heart disease complicated with arrhythmia. Methods：A total of 80 cases of patients with coronary heart disease complicated with arrhythmia were selected and divided into the observation group and the control group according to the random number table method，40 cases in each group．The control group was treated with metoprolol tartrate tablets，and the observation group was additionally treated with modified Zhigancao tang based on the treatment of the control group ． Both groups were treated for four weeks. The clinical effect，levels of blood lipids indexes，indexes of the heart function， and level of C-reactive protein (CRP) were compared between the two groups. The adverse reactions in the two groups were compared. Results：The total effective rate was 97.5% in the observation group，higher than that of 80.0% in the control group(P＜0.05)． After treatment， the levels of triglyceride (TG)， total cholesterol (TC)， and low- density lipoprotein cholesterol (LDL-C) in the two groups were decreased when compared with those before treatment(P＜0.05)，and the levels of high-density lipoprotein cholesterol (HDL-C) were increased(P＜0.05)．After treatment，levels of TG，TC，and LDL-C in the observation group were lower than those in the control group(P＜0.05)，and HDL-C level was higher(P＜0.05). After treatment， when compared with those before treatment， scores of left ventricular ejection fraction and myocardial contraction force in the two groups were increased(P＜0.05)，the heart rate quickened(P＜0.05)，and levels of CRP decreased(P＜0.05)． After treatment， when compared with those in the control group， score of left ventricular ejection fraction and myocardial contraction force in the observation group were larger(P＜0.05)，the heart rate faster(P＜0.05)，and the CRP level lower(P＜0.05). There were no obvious adverse reactions in the two groups. Conclusion： The therapy of modified Zhigancao tang combined with metoprolol tartrate tablets in treating coronary heart disease complicated with arrhythmia can effectively improve the clinical symptoms，blood lipids indexes，and the heart function. Its curative effect is better than simple metoprolol tartrate tablets ．