To analyze the effect of 3D printing technology in Salter pelvic osteotomy for children with developmental dislocation of the hip (DDH). [Methods] 46 cases (46 hips) of children with DDH treated by Salter pelvic osteotomy from June 2015 to June 2018 were retrospectively analyzed. Among the 46 cases, there were 7 males and 39 females, 30 were left dislocations and 16 were right dislocations, the age ranged from 6 months to 8 years, with an average of (3.02±0.58) years old. All children underwent CT scans before surgery, simulated surgery based on CT scan data, and guided the surgery with 3D printing technology. The parameters of preoperative digital model and 3D printing physical model were compared. The acetabular index (AI) of the affected side and the uninjured side were compared. The patients were followed up for 6 to 12 months, and the complications and hip function were evaluated. [Results] There was no significant difference between 3D printing physical model and 3D digital model (P > 0.05). All children successfully completed the operation, the operation time was (52.33±7.52) min, the blood loss was (45.35±5.01) mL, and the postoperative hospitalization was (7.20±1.55) days. No serious complications such as neurovascular injury and wound infection occurred during and after the operation. During the follow-up period of (10.35 ± 3.01) months, no serious complications such as re dislocation, avascular necrosis of femoral head and deformity of hip wing occurred. At the last follow-up, the excellent and good rate of hip joint function was 100%. Compared with that before operation, AI of affected side decreased with time (P < 0.05). The AI of the ipsilateral side before, immediately after, 6 weeks and 6 months after the operation was higher than that of the healthy side (P < 0.05). There was no significant difference in AI between 12 months and 18 months after operation (P > 0.05). [Conclusion] 3D printing technology can obtain satisfactory surgical results in the treatment of children's DDH Salter pelvic osteotomy, restore normal function of the hip joint without serious complications.