Objective To analyze the effect of Twin-Block two-phase orthodontics treatment on occlusal function and cephalometric indicators in children with early mandibular retrognathia. Methods A total of 100 children with early mandibular retrognathia admitted to Universal Xi'an Beihuan Hospital from May 2019 to May 2022 were selected, and they were divided into the control group and the observation group by the random number table method, with 50 children in each group. The control group was treated with simple straight wire appliance orthodontics technology, and the observation group was treated with Twin-Block twophase orthodontics treatment. The occlusal function, cephalometric indicators and complication rate were compared between the two groups. Results The occlusal function score of the observation group after intervention was higher than that of the control group (P <0.05). After intervention, the ANB angle of the observation group was smaller than that of the control group, and the SNB angle was larger than that of the control group (P <0.05). There were no statistically significant differences in SNA angle and Mp-SN angle between the two groups (P >0.05). The incidence of complications in the observation group (2.00%) was lower than that in the control group (20.00%) (P <0.05). Conclusion Compared with simple straight wire appliance orthodontics technology, Twin-Block two-phase orthodontics treatment has a better effect in improving the sagittal relationship of the maxilla and mandible in children with early mandibular retrognathia. It can effectively reduce the ANB angle, increase the SNB angle, improve the occlusal function of children, and has a lower incidence of complications after treatment, with higher safety.