Abstract: Objective　 To examine the effect of the lateral peterygoid muscle in the reconstruction the condylar shape during the sagittalfracture of mandibular condyle (SFMC) healing process. Methods　Twenty four adult sheep were randomly divided into 2 groups, All sheep had a uniateral operation on the right side of cuting anterior and posterior attachments of the the discs ,and an oblique vertical osteotomy was made from the lateral pole of the condyle to the medial side of the condylar neck. One group (group A) Keep pterygoid muscle in the attached condylar free, and exercise their functions. The other group (group B) In the perioperative cut pterygoid muscle in the attached condylar free, to block its function . Each group sheep were sacrificed at 2 weeks、4 weeks、12 weeks、and 24 weeks after surgery, And separation of complete TMJ general under the microscope, According to the TMJ sagittal direction in the third and divided into fixed, HE staining and paucean tuichrome staining. Result　In the group without cut the the lateral peterygoid muscle.the joints showed greater overgrows of new bone more advanced ankylosis. Conclusion　This study shows that the lateral pterygoid muscle plaied very important role the reconstruct the condylar shape during the sagittalfracture of mandibular condyle (SFMC) healing process.