Objective：To explore the effects of gradual mandibular forward on condyle position changes among patients with obstruc－tive sleep apnea hypopnea syndrome（OSAHS）. Methods：Three-dimensional finite element model of mandible and temporomandibu－lar joint was constructed using CT，Mimics，Imageware and Ansys software. Changes in positions of joint space（anterior，superior and posterior） were estimated when mandible forward in 20%，40%，60%，68%，70%，75%，80% and 100% of the maximum protrusion. Results：As the mandible gradually forwarding，joint spaces underwent corresponding changes. With the increase in forward level of the mandible，displacement of the joint space was also increased；the most obvious gap was the anterior，followed by the superior and posterior. Conclusions：Observation on condyle position changes in patients with OSAHS provides a theoretical basis for clinical use of oral appliance in the treatment of patient with OSAHS from the temporomandibular joint.