The invention discloses an oral maxillo-mandibular relationship reestablishment aid device, and a reestablishing method and device, relating to the field of stomatology. The oral maxillo-mandibular relationship reestablishment aid device comprises: a maxillary gasket used for fixing a maxillary model, wherein positioning marks are provided on the side surface of the maxillary gasket and used for positioning the maxillary gasket; a mandibular gasket used for fixing a mandibular model, wherein positioning marks are provided on the side surface of the mandibular gasket and used for positioning the mandibular gasket; a base comprising an upper base used for limiting the height of the maxillary gasket and a lower base used for placing the mandibular gasket; and a support structure used for fixing the upper base and the lower base. Such an oral maxillo-mandibular relationship reestablishment aid device enables an operator to obtain a maxillary gasket and a maxillary model, as well as a mandibular gasket and a mandibular model, that are fixedly connected and keep a certain positional relationship, and obtain maxilla scan data and mandible scan data under a predetermined maxillo-mandibular relationship from scan data by means of the positioning marks, thereby reducing the number of scans and improving the efficiency and precision.