Objective To investigate the feasibility and effectiveness of self-made auxiliary devices in assisting the guide pin placement and precise temporary fixation of the main nail in proximal femoral nail antirotation (PFNA) internal fixation of intertrochanteric fractures. Methods A prospective randomized controlled study was conducted to analyze the clinical data of 60 patients with femoral intertrochanteric fractures over 65 years old who met the selection criteria between January 2020 and June 2022 and were treated with PFNA internal fixation. The patients were randomly divided into the trial group (auxiliary device guided main nail guide pin placement and temporary fixation) and the control group (conventional treatment), with 30 cases in each group. There was no significant difference in baseline data such as gender, age, cause of injury, time from injury to operation, fracture side, AO/Orthopaedic Trauma Association (AO/OTA) classification, and combined medical diseases between the two groups (P>0.05). The operation time, times of main nail guide pin placement, intraoperative fluoroscopy frequency, intraoperative blood loss, and perioperative blood transfusion were recorded and compared between the two groups. The quality of fracture reduction was evaluated by CHANG Shimin et al. Harris score was used to evaluate the hip function at 1 year after operation. Results In the trial group, 2 temporary fixation needles were successfully placed 2-5 times, including 2 times in 13 cases (43.3%), 3 times in 8 cases (26.7%), 4 times in 7 cases (13.3%), and 5 times in 2 cases (6.7%). The operation time, times of main nail guide pin placement, intraoperative fluoroscopy frequency, and intraoperative blood loss in the trial group were significantly less than those in the control group, and the reduction quality score was significantly better than that in the control group (P<0.05). There was no significant difference in perioperative blood transfusion between the two groups (P>0.05). All patients were followed up 12-19 months (mean, 15 months). There was no complication such as incision infection, deep vein thrombosis, and internal fixation loosening. At 1 year after operation, the Harris score of the affected hip joint in the trial group was significantly higher than that in the control group (P<0.05). Conclusion The technique of main nail guide pin placement and temporary fixation under the guidance of auxiliary devices in PFNA internal fixation can achieve faster insertion of the main nail guide pin, accurate temporary fixation to maintain reduction, and avoid the subsequent operation space, so as to improve the effectiveness.