Objective：To observe the clinical effect of Shensong Yangxin capsules combined with theophylline for arrhythmia and its safety.Methods：Divided 60 cases of patients with arrhythmia into two groups randomly，30 cases in each group.The control group was treated with routine western medicine and theophylline sustained release tablets orally.The observation group was additionally treated with Shensong Yangxin capsules based on the treatment of the control group.The treatment of both groups lasted for four weeks.Observe the clinical effect，cardiothoracic ratio，blood pressure，changes in heart rate，arrhythmia，heart rate variability including the standard deviation of the averages of normal-to-normal RR intervals of sinus in all 5-minute segments(SDANN)，the standard deviation of normal-to-normal RR intervals(SDNN)，the root mean square of successive differences between adjacent RR(RMSSD)，and other changes in the two groups.Results：The total effective rate was 93.33%in the observation group and 60.00%in the control group，the difference being significant(P＜0.05).After treatment，the cardiothoracic ratio(except for that in the control group)，systolic pressure，diastolic pressure and heart rate in the two groups were all decreased when compared with those before treatment(P＜0.05)；the above indexes in the observation group were improved more significantly when compared with those in the controlgroup(P＜0.05).After treatment，the times of premature ventricular contraction，premature atrial contraction and premature contraction of atrioventricular junction in the two groups were significantly decreased when compared with those before treatment(P＜0.05)；the times of the above indexes in the observation group were less than those in the control group(P＜0.05).After treatment，the levels of SDANN，SDNN and RMSSD in the two groups were increased when compared with those before treatment(P＜0.05)；the above indexes in the observation group were improved more significantly when compared with those in the control group(P＜0.05).The incidence of adverse reactions was 3.33%in the observation group and 6.67%in the control group，the difference being not statistically significant(P＞0.05).Conclusion：The therapy of Shensong Yangxin capsules combined with theophylline for arrhythmia has more significant therapeutic effect than simple administration of western medicine，which is worthy of promotion and application.