Abstract: Objective?To discuss a modified positioning method of right-sided double-lumen endobronchial tube (RDLT) for removing right upper lobe (RUL) obstruction.?Methods?70 ASA II or III patients with RDLT intubation scheduled for thoracoscopic surgery (48 men and 22 women) was enrolled, aged 18?~?78 years. All the patients were randomly assigned into two groups: conventional group (inflated bronchial cuff just below the carina, group C) and modified group (1/3?~?1/2 inflated bronchial cuff above the carina, group M), 35 patients in each group. Primary outcomes measures: The RDLT insertion depth and the number of cases of RUL obstruction. The right mainstem bronchus (RMB) length. The number of cases of RDLT malposition and bronchial cuff herniation after lateral decubitus position. The effect of left lung collapse at the moment of chest opened and 30 min later.?Results?The RDLT insertion depth of group M was significantly shorter than that of group C (P??0.05). In group C, the RMB length of patients with RUL obstruction was shorter than that of patients without RUL obstruction (P??0.05). The number of cases of bronchial cuff herniation in group M were more than that in group C (P??0.05).?Conclusion?The modified RDLT positioning method can reduce the occurrence of RUL obstruction, especially for patients with short RMB, which can be used to relieve RUL obstruction caused by conventional positioning method. The RDLT can also be located directly by this method, but the RDLT prolapse from RMB must be vigilant.