Abstract： Objective： To observe the clinical effect of Zhigancao tang combined with metoprolol succinate sustainedrelease tablets for premature ventricular contractions. Methods： A total of 92 cases of patients with premature ventricular contractions who were admitted and treated from March 2017 to March 2019 were screened out. All patients were divided into two groups according to the random number table method， 46 cases in each group. The control group was given metoprolol succinate sustained- release tablets，and the observation group was additionally given Zhigancao tang based on the treatment of the control group. Both groups were treated for four weeks. The curative effect was observed and evaluated in the two groups. The indexes of heart rate variability including the standard deviation of normal to normal(SDNN) of sinus beat R-R interval，the standard deviation of the averages of normal-to-normal(SDANN) of R-R interval，and the root mean square of the successive differences(RMSSD) of adjacent R- R interval were compared between the two groups. The total number of premature ventricular contractions in 24 h and the clinical effect were compared between the two groups. Results： After treatment， SDNN， SDANN， and RMSSD in the two groups were significantly increased， the difference being significant(P＜0.01)；the three indexes in the observation group were significantly higher than those in the control group，the difference being significant(P＜0.01). The total number of premature ventricular contractions in 24 h in the two groups was significantly decreased，the difference being significant(P＜0.01)；the total number in the observation group was significantly less than that in the control group，the difference being significant(P＜0.01). The clinical effect evaluated with the frequency of premature ventricular contractions in the observation group was significantly better than that in the control group， the difference being significant(P＜0.05). The clinical effect evaluated with premature ventricular contractions classification in the observation group was significantly better than that in the control group， the difference being significant(P＜0.05). Conclusion： In the treatment of premature ventricular contractions， the combination therapy of Zhigancao tang and metoprolol succinate sustained-release tablets can improve heart rate variability，reduce the seizure frequency and grade of premature ventricular contractions，whose clinical effect is better than that of simple western medicine.