Objective To study the modeling method of rat model and the air flow characteristicwith its upper stenosis-airway. Methods Thirty-two 3-month old rats were randomly divided into two groups: the control group and the model group. For the model group, sodium hyaluronte of 0.1 mL was injected into mucosa of the soft palate and uvula in each rat under the anesthetic state. After feeding under the same condition for 3 months, CT scans and respiratory experimental examinations were performed on the two groups, respectively. The computational fluid dynamic (CFD) method was then employed to simulate the airflow in their upper airway. The flow characteristics were compared between the control rat and the model rat. Results (1) The minimum cross-sectional area of pharyngeal in the model group was reduced remarkably than that of the control group, showing that the airway of the model rats was significantly narrower than that of the control rats (P<0.05). (2) The model rats became breathless, and their respiratory period became unsteady. The breath intensity of the model rat on the pharynx fluctuated more rapidly. (3) The maximum wall shear stress on the pharynx of the control rat was scattered at the respiratory phase while it was concentrated for the model rat. Conclusions The injection of sodium hyaluronte into mucosa of the soft palate and the uvula can induced the narrowness of the upper airway in the model rat, which is similar to patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) in pathology. The narrowness of the upper airway can cause dyspnea and extend respiratory period. The shear stress on the pharynx of the upper stenosis-airway induces stronger damage to the pharynx tissue, especially to the soft palate and uvula, which aggravates reconstruction of the pharynx tissue.