Objective To compare the clinical effect of external fixation frame to treat Tile B type pelvic fracture with or without combined pubic branch nailing. Methods The clinical data of 42 pelvic fracture patients treated surgically from January 2019 to April 2022 were retrospectively analyzed, and based on the results of preoperative doctor-patient communication, 22 cases were treated with external fixation with combined iliac-pubic branch nailing (pubic nailing group), and the other 20 cases were treated with external fixation with simple iliac nailing (no pubic nailing group). The perioperative period, follow-up and imaging data of the two groups were compared. Results The operation was successfully completed in both groups, and no important vascular and nerve injuries occurred. The no pubic bone nail group was better than the pubic bone nail group in terms of operation time, total length of incision, intraoperative blood loss and number of intraoperative fluoroscopies (P<0.05), but the pubic bone nail group went down to the ground significantly earlier than that of the no pubic bone nail group [(22.77±2.41) d vs. (41.85±3.84) d, P<0.05], and the length of hospitalization was significantly less than that of the no pubic bone nail group [(12.18±1.84) d vs. ( 19.35±2.81) d, P<0.05]. In both groups, the time to full weight bearing was significantly earlier in the pubic nail group than in the group without pubic nail [(45.73±6.61) d vs (60.70±9.40) d, P<0.05] at a follow-up of more than 12 months. The VAS score, hip extension and flexion ROM, internal and external rotation ROM, and Majeed score improved significantly with postoperative time in both groups (P<0.05); the above indexes in the pubic bone nail group were significantly better than those in the group without pubic bone nailing in the first month after surgery (P<0.05). In terms of imaging, there was no statistically significant difference in the quality of fracture reduction and and fracture healing time between the two groups (P>0.05). Conclusion The clinical effect of the combined iliopubic-pubic branch pinning external fixation brace for Tile B pelvic fracture is better than that of the no pubic bone nail brace.