Ｏｂｊｅｃｔｉｖｅ　To investigate the minimum alveolar concentration of sevoflurane for endotracheal intubation in children who underwent tonsillectomy and adenoidectomy under inhalation anesthesia induction without the use of muscle relaxants.　Methods　A total of sixty-three patients [American Society of Anesthesiologists(ASA) Ⅰ or Ⅱ] undergoing tonsillectomy and adenoidectomy were divided into two groups: a neutral head position group (n=27) and a rotary head position group (n=36) according to the random number table. General anesthesia was induced with 8% sevoflurane. After the loss of the eyelash reflex, the vapourizer was adjusted, so that the end-tidal sevoflurane concentration reached the preset concentration, and maintain for 10 min, followed by endotracheal intubation. The intubation score was assessed using Helbo-Hansen score scale. For each group, the concentration of sevoflurane used for each consecutive patient was increased or decreased using the Dixon′s up-and-down method based on the success or failure to achieve adequate conditions for intubation in the previous patient. The adjacent concentration gradient was 0.5%.　Results　In the neutral head position group, the minimum alveolar concentration (MAC) of sevoflurane for endotracheal intubation was (4.30±0.44)%, where the median effective dose (ED50) was 4.30%, and the 95% effective dose (ED95) was 4.99%. In the rotary head position group, the MAC of sevoflurane for endotracheal intubation was (3.45±0.54)%, where the ED50 was 3.45%, and the ED95 was 4.62%.　Conclusions　The head position of rotating 45° was superior to the neutral head position, which can significantly reduce the MAC of sevoflurane for endotracheal intubation in children undergoing tonsillectomy and adenoidectomy.