Objective:To observe the effect of modified Zhigancao Decoction combined with metoprolol in the treatment of non-valvular atrial fibrillation(NVAF).Methods:Ninety-two cases were randomly divided into two groups,46 cases in each group.Both groups were treated with metoprolol,and the observation group were treated with modified Zhigancao Decoction in addition.Results:The total effective rate of the observation group was higher than that of the control group(P<0.05).After treatment,the scores of palpitation,burning sensation of five centers,shortness of breath,insomnia and dreaminess,left ventricular end-systolic diameter(LVESD),left ventricular end-diastolic diameter(LVEDD),left atrial diameter(LAD)and ICAM-1 in the observation group were lower than those in the control group,and left ventricular ejection fraction(LVEF)and tPA were higher than those in the control group(P<0.05).The adverse reactions of the two groups were similar(P>0.05).Conclusion:Modified Zhigancao Decoction combined with metoprolol is effective in the treatment of NVAF,without serious adverse reactions.