Objective To explore the morphological change of upper airway in obese patients with multislice spiral CT (MSCT) scan and post-processing techniques and to reveal the relationship between structural abnormalities and the severity of obstructive sleep apnea hypopnea syndrome (OSAHS).Methods Adults with obesity were enrolled and divided into OSAHS group (n =25) and non-OSAHS group (n =25) based on polysomnography (PSG).MSCT covering upper airway was performed and measurements of soft tissue,bone structure and spatial structure of the upper airway were obtained from a 3-dimensional segmentation using image analysis.And their relationship between body mass index(BMI),neck circumference,apnea hyponea index(AHI) were analyzed.Results Compared with non-OSAHS control group,the area of the soft palate was significantly increased (P ＜ 0.05).The volume of the soft palate was further significantly increased (P ＜0.01);The cross-sectional area,anteroposterior diameter and volumes of the oropharynx in OSAHS group were decreased (P ＜ 0.05).The volume of the soft palate had significant positive correlation with BMI and AHI (P ＜ 0.01).Conclusion MSCT can evaluate obese patients from 2 days and 3 days structure on airway obstruction and surrounding soft tissues,and these results suggest the soft palate volume may be associated with severity of OSAHS.