An oral maxillo-mandibular relationship reestablishment aid device, and reestablishing method and device, relating to the field of stomatology. The oral maxillo-mandibular relationship reestablishment aid device comprises: a maxillary gasket (1) used for fixing a maxillary model, wherein positioning marks (2) are provided on the side surface of the maxillary gasket (1) and used for positioning the maxillary gasket (1); a mandibular gasket (3) used for fixing a mandibular model, wherein positioning marks (4) are provided on the side surface of the mandibular gasket (3) and used for positioning the mandibular gasket (3); a base (5) comprising an upper base (6) used for limiting the height of the maxillary gasket (1) and a lower base (7) used for placing the mandibular gasket (3); and a support structure (8) used for fixing the upper base (6) and the lower base (7). Such an oral maxillo-mandibular relationship reestablishment aid device enables an operator to obtain a maxillary gasket (1) and a maxillary model, as well as a mandibular gasket (3) 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 (2, 4), thereby reducing the number of scans and improving the efficiency and precision.