The main manifestation of jaw deformity in children with cleft lip and palate during the mammoglossal period is the collapse and torsion of the maxillary arch because the small bone segment on the lateral side of the unilateral cleft lip and palate is free and has no contact with the plow bone and nasal septum, whereas the healthy bone segment is in contact with the pear bone and nasal septum, and the development of the nasal septum can potentially affect the position of the healthy bone segment, eventually causing the small bone segment to sink and the anterior jaw area to twist upward and outward. In children with cleft lip and palate who have undergone PNAM treatment in the neonatal period, the treatment of the mammillary row is focused on making full use of the growth potential to achieve blocking or guiding orthodontic treatment, i.e. to maintain the PNAM treatment effect and induce normal development of the jaws. In children with cleft lip and palate with jaw deformities, the main goal of orthodontic treatment during the molar row is to correct the collapse and torsion of the maxillary arch, including lateral and anterior enlargement. The orthodontic treatment methods include open square arch wire fixed orthodontic treatment, maxillary open pavement fixed orthodontic treatment, screw expansion fixed orthodontic treatment, Quadhelix orthodontic treatment, Cleat orthodontic treatment, split reed orthodontic treatment, and reedless orthodontic treatment. The treatment process should take into account the resistance to adverse muscle forces, so that the orthodontic forces extend to the palatal and alveolar processes of the maxilla. The early orthodontic treatment for children with cleft lip and palate in the molar period starts at the age of 4. The orthodontic treatment mainly includes anterior maxillary traction and rapid maxillary arch expansion, aiming at correcting sagittal and horizontal malocclusion of the jaws and guiding their coordinated development. Correction of anterior retrusion – maxillary anterior traction Components: external traction device, i.e., mask: apply backward and upward force to the mandible and condyles; internal maxillary splint type co-pad (inter-adjacent hook retention): intra-oral co-pad is bonded to the teeth using glass ionomer to prevent movement of the teeth; external elastic traction collar: connect the traction hook to the external mouth through the collar to achieve anterior traction. The anterior traction is achieved by a skin ring connecting the traction hook to the extra-oral hood. Correction of posterior retrusion – maxillary rapid arch expander. There is still growth potential during the milking period, and functional correction of posterior retrusion should be performed during this period. Case presentation Case 1: LSH, female, right cleft lip and palate, cleft alveolus Case 2: DST, 4 years old, right cleft lip and palate, cleft alveolus Case 3: ZJQ, male, second gill arch syndrome Case 4: LTQ, male, 4 years old, right cleft lip, cleft alveolus The significance of early orthodontic treatment of children with cleft lip and palate in the mammary dentition is to remove the spark to prevent it from starting a fire. The results of arch expansion treatment are fast; improve the alignment of permanent teeth; release the locking knot in the anterior alveolar area; improve the articulation of speech; and enable the patient to obtain normal tongue posture and nasal breathing early.