Abstract: Objective To analyze the characteristics of the electrocardiogram （ECG） in patients with dengue. Methods Clinical data of 302 cases of dengue （dengue group） and 300 healthy subjects （control group） during the same period were retrospectively analyzed. The abnormalities of ECG were statistically compared between two groups. The changes and abnormalities of ECG before and after treatment were subsequently analyzed. Results The proportion of patients with abnormal ECG in the dengue group was 51.32%（155/302）, significantly higher than 31.00%（93/300） in the control group （P < 0.001）. In the dengue group, the frequency of abnormal ECG in terms of ST-T changes （27.81%, 84/302） and sinus bradycardia （11.92%, 36/302） was significantly higher than that in the control group （both P < 0.05）. Forty-six patients with abnormal ECG were reexamined by ECG after corresponding treatment. Among them, the frequency of sinus bradycardia was remarkably decreased compared with that before treatment （P < 0.05）. Among 36 dengue patients with sinus bradycardia, 16 cases （44.44%） had ST-T changes, and the proportion was significantly higher than 25.56% （68/266） of their counterparts without sinus bradycardia （P < 0.05）. Conclusions ECG abnormalities are commonly observed in dengue patients, mainly manifested as ST-T changes and sinus bradycardia. Sinus bradycardia is the most common arrhythmia of dengue and a relatively prominent ECG feature, which may have certain hints for the clinical diagnosis of dengue.