Abstract：Objective：To discuss the effect of Shenmai injection on electrocardiogram changes in patients with coronary heart disease of different Chinese medicine syndrome types. Methods： According to the theory of Chinese medicine syndrome differentiation， a total of 271 cases of patients with coronary heart disease who were treated with Shenmai injection were divided into four groups of Chinese medicine：the group of heart-kidney yin deficiency(72 cases)，the group of phlegm- turbidity obstruction(69 cases)，the group of heart blood obstruction(56 cases)，and the group of qi-yin deficiency (74 cases). A total of 67 cases of patients with coronary heart disease who were given simple western medicine at the same period were randomly selected as the control group. Before and after treatment，minimum corrected QT interval(QTcmin)， maximum corrected QT interval(QTcmax)，and corrected QT interval dispersion(QTcd) of electrocardiogram were compared in the five groups； minimum corrected JT interval(JTcmin)， maximum corrected JT interval(JTcmax)， and corrected JT interval dispersion(JTcd) were compared in the five groups；the number of cases of atrioventricular block，ischemic T wave， and abnormal ST segment was compared in the five groups. PTF-V1 was defined as the product of the duration and amplitude of the P-wave during the negative phase shown in lead V1. The number of cases of PTF-V1≤-0.04 mm·s was measured. Results： After treatment， there was significant difference being found in the comparison of indexes including QTcmin， QTcmax， and QTcd among the five groups(P＜0.05). After treatment， the QTcmin， QTcmax， and QTcd in the qi- yin deficiency group were decreased when compared with those in the control group as well as the groups of heart-kidney yin deficiency，heart blood obstruction，and phlegm- turbidity obstruction；the QTcd in the four groups of Chinese medicine were lower than that in the control group，the difference being significant(P＜0.05). After treatment，there was significant difference being found in the inter-comparison of indexes including JTcmin，JTcmax，and JTcd among the five groups(P＜ 0.05). After treatment，JTcmin，JTcmax，and JTcd in the qi- yin deficiency group were decreased when compared with those in the control group as well as the groups of heart- kidney yin deficiency， heart blood obstruction， and phlegmturbidity obstruction；JTcd in the four groups of Chinese medicine were significantly lower than that in the control group，the difference being significant(P＜0.05). After treatment，there was significant difference being found in the comparison of the incidence of PTF- V1≤-0.04 mm·s and atrioventricular block among the five groups(P＜0.05)；the above incidence in the group of qi- yin deficiency was lower than those in the control group and the group of heart- kidney yin deficiency， the difference being significant(P＜0.05). Conclusion：For coronary heart disease of different Chinese medicine syndrome types， Shenmai injection can effectively decrease indexes of electrocardiogram， namely， QTcmin， QTcmax， QTcd， JTcmin， JTcmax and JTcd，and reduce the number of cases of atrioventricular block and PTF-V1≤-0.04 mm·s，which has significant improvement on qi-yin deficiency type.