Objective: To explore and analysis the application value of multi-slice spiral CT three-dimensional reconstruction technology in the determination of lower limb force lines and hip joint function after internal fixation surgery for hip fractures. Methods: From June 2024 toMay2025, 79 cases of patients who underwent internal fixation surgery for hip fractures treated in our hospital were selected as the study subjects. All patients were underwent three-dimensional reconstruction with multi-slice spiral CT 3 days after surgery, and the lower limb force line status was recorded. The hip joint function of the patients was determined 3 months after surgery. Results:Three months after operation, the hip function of 79 patients was judged as excellent in 52 cases, good in 14 cases, fair in 10 cases, poor in 3 cases, and the excellent and good rate was 83.54%. The hip, knee and ankle Angle, posterior inclination Angle of tibial plateau, femoral varus Angle, tibial Angle and femoral Angle in the excellent group were higher than those in the non-excellent group (P<0.05). The fracture healing time and postoperative hospital stay in the excellent group were shorter than those in the non-excellent group (P<0.05), and the postoperative drainage volume was lower than that in the non-excellent group (P<0.05). The incidence of wound infection, urinary retention, venous thrombosis and wound hematoma in the excellent group was 4.55%, lower than that in the non-excellent group (23.08%) (P<0.05).Conclusion: The hip joint function recovery of patients after hip fracture internal fixation surgery is relatively good. Multi slice spiral CT three-dimensional reconstruction technology can effectively predict the prognosis of patients after hip fracture internal fixation surgery by determining the lower limb force line, and has high clinical promotion and application value.