Objective To study the influence of nasal cavity structure on nasal function of warming and humidifying the inhaled airflow. Method Nine normal persons and two patients with deviation of nasal septum (pre and postoperation) were selected as research subjects. The threedimensional finite element model of nasal cavities of these volunteers was established. Numerical simulations for the airflow distribution, the airflow temperature and the airflow humidity in the nasal cavity were performed. Based on the simulation results, comparisons were made between normal nasal cavities and the patient’s nasal cavities as well as between the pre-and post-operative nasal cavities. ResultsIn the wider side of nasal cavity, the volume flow rate and the velocity of airflow were higher and the effect of warming and humidifying on the airflow was worse. For normal people, the nasal cavity for warming and humidifying the inhaled airflow was in the anterior segment of the nose. While for the patients, the main segment of warming and humidifying the inhaled airflow had to depend on the airway geometry. Conclusions The nasal cavity structure can influence the effect of warming and humidifying on the airflow. The parameters describing the geometry of nasal cavity, such as the surface area of nasal airway and volume of nasal cavity, may be a useful measurement for the nasal function of warming and humidifying the inhaled airflow.