Abstract: [Objective] To evaluate the long-term effect of preformed elastic intramedullary nail (ESIN) guided by three-dimensional reconstruction in the treatment of distal radius metaphyseal fracture (DMJ) in children. [Methods] The clinical data of 80 children with DMJ in our hospital and Pingmei Shenma medical group general hospital from January 2020 to February 2023 were analyzed retrospectively. Among them, 40 cases in the control group were treated with conventional C-arm perspective retrograde ESIN fixation, and 40 cases in the experimental group were treated with C-arm perspective three-dimensional reconstruction to guide preformed retrograde ESIN fixation. The perioperative period, follow-up and imaging data of the two groups were compared. [Results] The children in both groups successfully completed the operation and returned to the ward, and no vascular or nerve injury and incision infection occurred during the perioperative period. There was no significant difference in operation time, incision length, intraoperative blood loss and hospitalization time between the two groups (P>0.05). Compared with before operation, the elbow joint function score and wrist joint function score increased significantly at 4 weeks, 4 months and 6 months after operation, and there were statistical differences before and after different time points in the follow-up period (P<0.05), but there were no statistical differences in the above indexes between groups at the corresponding time points (P>0.05). The incidence of secondary fracture displacement in the experimental group was lower than that in the control group (P<0.05). Compared with preoperation, the radial height, palmar inclination angle and ulnar deviation angle increased significantly at 4 weeks, 4 months and 6 months after operation (P<0.05). There were statistical differences before and after different time points in the follow-up period (P<0.05). At the corresponding time points, the radial height and palmar inclination of the experimental group were higher than those of the control group (P<0.05). There was no statistical difference between the two groups (P>0.05). [Conclusion] Three-dimensional reconstruction-guided preformed retrograde ESIN fixation in children's DMJ can improve the stability of reduction and the reduction of postoperative fracture, which is of great significance to reduce the incidence of secondary displacement of postoperative fracture.