Objective To explore the feasibility and effectiveness of maintaining the reduction of unstable intertrochanteric fractures by Kirschner wire-fixation-cortical bone technique. Methods Forty patients with intertrochanteric fracture [AO/Orthopaedic Trauma Association (AO/OTA) type 31-A2.2] admitted between May 2015 and January 2017 and requiring closed reduction and proximal femoral nail antirotation (PFNA) were randomly divided into trial group (intraoperative Kirschner wire-fixation-cortical bone technique group, 20 cases) and control group (conventional treatment group, 20 cases). There was no significant difference in general data of gender, age, side, body mass index, cause of injury, time from injury to operation between the two groups (P>0.05). The operation time, intraoperative blood loss, and intraoperative fluoroscopy times of the two groups were recorded; the reduction quality of fracture was observed according to the corresponding relationship between medial and anterior cortex (positive, neutral, and negative support) of intraoperative fluoroscopy proposed by ZHANG Shimin, and the stability of internal fixation and fracture healing were observed; Harris score was used to evaluate the recovery of hip function at 12 months after operation. Results In the trial group, 6 cases (30%) had 2 Kirschner wires implanted less than 4 times, 7 cases (35%) had 5-8 times, and 7 cases (35%) had 9 times or more. There was no significant difference in operation time and intraoperative blood loss between the two groups (P>0.05), but the blood transfusion volume and intraoperative fluoroscopy times in the trial group were significantly less than those in the control group (P<0.05). Both groups were followed up 13-21 months, with an average of 17 months. There was no complications such as wound infection, deep venous thrombosis of lower extremities, refracture, and internal fixation-related complications. The quality of intraoperative reduction in the trial group was significantly better than that in the control group (Z=–2.794, P=0.024). The Harris score of the trial group was significantly better than that of the control group at 12 months after operation (t=2.98, P=0.01). Conclusion The use of Kirschner wire-fixation-cortical bone technique during intertrochanteric fracture closed reduction and PFNA internal fixation surgery can effectively maintain the reduction effect, reduce the number of fluoroscopy, improve the reduction quality, reduce allogeneic blood input, obtain better hip function, and do not increase the operation time and intraoperative blood loss.