Objective To investigate the change of corrected QT dispersion (QTcd) before and after stone removal by therapeutic endoscopic retrograde cholangiopancreatography (ERCP) and the related influencing factors. Methods A total of 61 patients who underwent therapeutic ERCP for stone removal in our hospital from June 2018 to January 2019 were consecutively enrolled as subjects. Resting 12-lead electrocardiography (ECG) was performed before and in 3h and 24h after operation. The patients with QTcd in 3h after operation higher than the value before were assigned into QTcd-increased group, otherwise were into QTcd-reduced group. Statistical analysis was performed using SPSS 23.0. Student t test or Chi-square test was used for comparison between groups on different data types. Multivariate logistic regression analysis was applied to screen the risk factors of QTcd increase at 3h post-ERCP. Results Among the 61 patients, 1 of them experienced ventricular fibrillation immediately after ERCP, and so complete data were obtained from the left 60 patients. The average QTcd value was (29.05±11.09), (36.00±13.46) and (21.81±10.52)ms respectively, before and at 3h and 24h post-ERCP. The value at 3h after ERCP was significantly higher than those at the other 2 time points (P<0.05). Multivariate logistic regression analysis showed that female (OR=15.895,5%CI 2.505-100.853) and estimated glomerular filtration rate (eGFR, OR=1.039,5%CI 1.003-1.077) were the risk factors for QTcd increase at 3h post-ERCP. Conclusion Therapeutic ERCP can lead to QTcd increase in a short time (3h) after stone removal by ERCP, which suggesting increased risk for malignant arrhythmia at that duration. Female and eGFR are the risk factors for QTcd increase at 3h post-ERCP.