〔Abstract〕 Objective To evaluate the value of multi-detector CT(MDCT) upper airway imaging in the diagnosis of obstructive sleep apnea hypopnea syndrome(OSAHS) and in determining the location of upper airway obstruction. Methods MDCT was used to scan the upper airways of 85 clinically confirmed adult patients with different degrees of OSAHS(73 males and 12 females) in calm breathing phase and forced inhalation phase and 60 normal adults(50 males and 10 females) in calm breathing phase to obtain nasal cavity,nasopharynx,palatopharynx and oglosopharynx volumes. Parapharyngeal fat volume was measured in OSAHS patients and normal subjects. In addition,three groups of clinical data related to OSAHS patients were recorded,including sleep apnea hypopnea index(AHI),body mass index(BMI) and lowest blood oxygen saturation(LaSO2). Finally,the measured data and clinical data of each group were statistically analyzed. Results The volume of nasopharynx and palatopharynx in the calm breathing group was significantly smaller than that in the control group,with statistical significance. Palatopharyngeal volume forced inspiratory phase was significantly smaller than calm breathing phase in the experimental group. The parapharyngeal fat volume in the experimental group was significantly higher than that in the control group. AHI was positively correlated with BMI and parapharyngeal fat volume. LaSO2was negatively correlated with AHI and BMI,respectively. Conclusion MDCT upper airway imaging has good clinical application value in the diagnosis,treatment and postoperative evaluation of OSAHS disease due to the significant anatomical difference between OSAHS patients and normal subjects.