Intermaxillary fixation is routine procedure to oral and maxillofacial area in jaw bone fracture, surgical correction of jaw deformity, osseus reconstruction of jaw. After transoral surgery, accompanied by intermaxillary fixation, dysphagia or airway obstruction may be followed due to blood clot, vomitus, or laryngeal spasm resulting from irritation by blood or secretions. Lingual or pharyngeal edema is other contributing factors of airway obstruction. In addition, intermaxillary fixation itself may cause obstruction of airway. In this study, pulmonary function test and arterial blood gas analysis were evaluated before and after intermaxillary fixation in 30 patients suffered from mandibular fractures. Comparative analysis was performed by estimated values. The results were as followed. 1. The spirometric values of FEV1, FEV1/FVC and FEF25-75% without intermaxillary fixation were reduced from 97.57%, 85.1%, 98.3,% to 71.7%, 66.5%, 61.2% with intermaxillary fixation, indicating the presence of obstructive pulmonary impairment. 2. Spirometric value of MVV, as the most influencing value of sensitive to extrapulmonary factors, was changed from 84.5% to 46.48%. 3. After intermaxillary fixation, the spirometric value of FVC, as indicator of restrictive pattern of pulmonary function, was not reduced significantly as measured from 94.47% to 89.97%. 4. $O_2$ saturation of arterial blood gas analysis without intermaxillary fixation was 97.86%. While intermaxillary fixation, $O_2$ saturation was 97.47%. The results indicate that careful airway management is mandatory undergoing intermaxillary fixation of various oral and maxillofacial surgery.