The pufpose of this study was to analyze the stress distribution and the displacement in the maxillary complex after the application of the three kinds of the head gear.(high pull head gear, straight pull head gear, cervical pull head gear.) Orthopedic force, 200 gram, was applied to the maxilla of the dry human skull in a high, straight and cervical direction. The stress distribution and the displacement within the maxillary complex was analyzed by a 3-dimensional finite element method. The results were as follow: 1. In corwn, the stress of cervical pull head gear was the greatest stress and straight pull head gear was the medium stress and high pull head gear was the least stress. 2. The compressive stress was observed on the anterior portion of premaxilla, especially anterior nasal spine area, when the three kinds of head gear were applied to the dry kuman skull. 3. In apeared that the stress of the anterior portion of thr zygomatic bone was greater than the posterior portion in the case of three kinds of head gear application and compressive stress was noted only at the below of the frontozyomatic suture of the zygomatic bone. 4. The backward, upward, sideward displacement of the alveolar area was observed in a high pull head gear application but in the case of straight pull head gear and cercical pull head gear application, the backward, downward, sideward displacement was observed. 5. The forward, downward, sideward displacement was observed on the midpalatine suture and premaxilla on the sagittal plane and transverse palatine suture in the case of three kinds of headgear application.