To provide further understanding of uncinate process, 15 uncinate processes were examined under scanning electron microscope, and 32 high-resolution coronal CT scans were studied in patients with septal deformity or sinusitis. It was found that(1)pathological ultrastructural changes of uncinate process were noted in patients with chronic sinusitis; (2) medially deviated, laterally deviated, pneumatization and hypertrophy of uncinate process were demonstrated. The following conclutions were drawn(1)the anatomic variations in ostiomeatal complex is responsible for the formation of chronic sinusitis; (2)for patients with chronic sinusitis, uncinatectomy is the treatment of choice; (3)preoperative and intraoperative studies of CT scans are mandatory for avoidance of complications.