Abstract: Objective: The purpose of this study is to investigate the biomechanical mechanism of the occlusal splint as an assistant therapy for the temporomandibular joint disorders (TMD) after joint reconstruction operation. Methods: The changes of stress distribution in the mandible of a patient with TMD after joint reconstruction operation during occlusal splint put on or not were analyzed quantitatively by combining spiral CT tomographic scanning technology with three dimensional finite element method. Results: Occlusal splint could evidently improve the distribution of maximum principal stress and minimum principal stress in each location in the mandible after joint reconstruction operation. The stress value in operated and nonoperated side of the mandible is reduced, in which the stress in the operated condyle is lowered more distinctly and effectively, and the stress symmetry of its each position is improved slightly also.Conclusion: Occusal splint can drop joint pressure, as well as obtain the symmetric load in bilateral temporomandibular (TMJ) in clinical application of postoperation. It is beneficial to restore the consistency in the function state of bilateral TMJ in order to assure the repair and reconstruction of the TMJ in a new normal condition.