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Objective The aim of this study was to investigate the flow and pressure distributions in the upper airway during respiration using computational fluid dynamics methods and in vitro experiments, and to test the accuracy of the numerical models. Methods An anatomically accurate finite element model of the human upper airway was constructed from magnetic resonance images, and an identical physical model of the same airway was built. Numerical simulations and experimental measurements were performed at flow rates of 200ml/s, 400ml/s, and 600ml/s, and the model-predicted distributions of the wall static pressure were compared with measured results. Results When the flow flux was the same, a larger pressure drop between the two ends of the upper airway was required during inspiration compared to expiration. That means a larger flow resistance during inspiration compared to expiration. The numerical predictions of the wall pressure at different locations of the upper airway were consistent with the measured data from the physical model. Numerical results showed high velocities in the retropalatal and retroglossal regions near the epiglottis during inspiration. Vortex flows occurred at the region below the uvula. During expiration, vortex flows could be observed at the region near the posterior top of the nasopharynx wall in the midsagittal plane, and in the nasopharynx and the oropharynx below the uvula in the coronal plane. Conclusions Numerical models can be used to simulate the flow field and pressure distribution accurately, as well as to show the flow characteristics in the upper airway intuitively. As noninvasive methods, in vitro models and numerical simulations could play an important role in the study on the pathogenesis and effective treatment methods of obstructive sleep apnea.