Abstract: To investigate the therapeutic effect of mandibular protrusive anti-snoring device on obstructive sleep apnea-hypopnea syndrome,a three-dimensional model of the upper airway of OSAHS patients is established based on CT images.Computational fluid dynamics method is employed to simulate the three-dimensional model of the upper airway,analyze the changes of fluid dynamics in the upper airway of OSAHS patients before and after using the anti-snoring device CFD-post is employed to post-process the simulation results.The research results show that the upper airway structures of OSAHS patients change after they wear anti-snoring devices,and the mandibular protrusive anti-snoring device can expand the upper airway volume of OSAHS patients,reduce the air flow rate and pressure in the upper airway,and help the patients to reduce their snoring.