Abstract：Objective The reconstruction of narrow airways and effects of air flow field on the airway wall under different breathing conditions were studied. Methods A three-dimensional model of human airway is established by using Mimics, and the flow field in the airway is simulated by computational fluid dynamics (CFD). The inner wall pressure and the distribution of airflow are analyzed and compared under different breathing states. Results Under different breathing conditions, the pressure value of endotracheal wall is relatively uniform in the endotracheal wall, but decreases significantly in the air inlet of the bronchial stenosis segment, and reaches negative pressure near the narrowest area. The airflow velocity decreases from the center of the pipe to the boundary layer, and the velocity reaches the maximum at the narrow area. Vortex is generated when airflow passes through the narrow area, and the larger the inlet flow velocity is, the larger the positive pressure and negative pressure values are, the more obvious the pressure drop at the narrow area is, and the more obvious the vortex phenomenon is. Conclusion The constriction of the airway stenosis area caused by negative pressure will lead to the patient's dyspnea, and the eddy current will cause the airway wall to be affected by the aerodynamic shear stress and may damage the airway wall mucosa. Therefore, the understanding of the pressure distribution and velocity distribution in the airway can provide a reference for the clinical diagnosis and treatment of airway stenosis.