Objective To investigate the clinical value of examining the anatomical position of right superior bronchus orifice preintubation by bronchoscopy on adjusting the position of right double-lumen endobronchial tube (R-DLT). Methods One hundred and sixty adult patients who were scheduled to intubate with R-DLT undergoing thoracic surgery were randomly assigned into two groups (n=80 per group): experimental group and control group. All patients were received intravenous anesthetics for induction. The length of right main bronchus and the position of right superior bronchus orifice in the transverse section of right main bronchus were measured prior to intubation by bronchoscopy in experimental group. The R-DLT was inserted into right bronchus by the conventional method and then adjusted the position by bronchoscopy in two groups. Bronchoscopy was performed through the tracheal lumen to ensure that the endobronchial portion of the DLT was in the right bronchus. The blue endobronchial cuff was just seen below the carina. In addition, lifted or inserted and twisted the tube properly according to the data measured in the experimental group. The relative position of orifices of the tube and the right upper lobe bronchus was assessed by bronchoscopy in the two groups. The R-DLTwas considered as effective preliminary location if right superior bronchus orifice was partly seen through the lateral orifice of R-DLT. The position of R-DLT was further adjusted till the three orifices of segmental bronchi were seen. Results In experimental group, the length of right main bronchus was (2.29±0.58)cm which was shorter than 1cm in 2 cases (2.5%). The central angle in the transverse section of right main bronchus between the central point of right superior bronchus orifice to 12 o’clock position was (94.5±8.3)° which was smaller than 75°or bigger than 105° in 4 cases (5.0%) in total. The number of effective preliminary location of R-DLT was 77(96.3%) in experimental group, and 62(77.5%) in control group, which showed significant difference between the two groups(P<0.05). There was 1 case (1.25%) failed intubation in each group, because of short distance within 1cm between right superior bronchus orifice and tracheal carina. Conclusion Examining the anatomical position of right superior bronchus orifice preintubation is helpful to improve effective preliminary location of R-DLT, and it is beneficial to find out anatomical variation and select appropriate airway tube.