Abstract: Objective:The purpose of this research was to further study the pathogenic mechanism of traumatic occlusion in craniomandibular disorders （CMD）.Methods:Animal model of traumatic occlusion was established by way of the wrought crown of unilateral mandibular molars of miniature pigs. The temporomandibular joint （TMJ） and the masticatory muscles of the pigs were observed and studied with histopathologic methods, immunohistochemical staining of substance P（SP） and prostaglandin E₂（PEG₂）, and radio-immunologic analyses of PGE₂ and PGE₂α. Results:The results indicated that such traumatic occlusion caused nociceptive reactions and pathologic changes in TMJ and masticatory muscles.Conclusion:The disc attachment and the synovial membrane of TMJ, the upper head of the lateral pterygoid muscle and the masseter are the target ougans of traumatic occlusion. It is shown that the pathogenic mechanism of the traumatic occlusion is borh neurogenous and non-neurogenous, and the interactons between peripheral and central nerves should alsobe taken into account.