After mastoidectomy and certain tympanoplasty procedure, the mastoid cavity often becomes a problem both to the patient and to the physician. Long periods of postoperative care are required due to incomplete healing with intermittent or continuous suppuration, and the necessity for repeated cleansing of epithelial debris from the cavity are not unusual occurrences. For several decades otologists have attempted to find successful ways to eliminate this cavity after such operation. We reported earlier the surgical technique which obliterated with cavity and simultaneously reconstructed the posterior canal wall and then made the ear close to normal anatomic structure, using Palva flap and cortical bone dust in cases with open cavity mastoidectomy. Using the previously mentioned technique we have got satisfactory results of rapid wound-healing, the external auditory canal close to normal anatomic structure and no need to cleanse the cavity repeatedly. We have observed the postoperative status of the mastoid cavity, the external auditory canal and the grafted bone dust by CT imaging of temporal bone and report the results.