Background In recent years, with the rapid development of medical, the anesthesiologists paid more attention to the preoperative evaluation of difficult airway ,and conducted a variety of clinical experiments. But these methods had ignored of the characteristics of the race, which anatomical marks and clinical factors are the best predictors is controversial. Objective To investigate the accuracy and reliability of airway assessment predictors in the clinical practice, and provide scientific reference for clinical practice. Content Introduce the definition of difficult airway,and the threshold and predictive power of these evaluation indicators were also summarized. Trend Anesthesiologists should not only enhance the power to predict difficult airway, but also need to master the emergency measures, in order to reduce the incidence of airway management failure.