To explore the differences of C-arm fluoroscopy and 3D imaging system of orthopedic surgery robot in closed reduction and internal fixation for femoral neck fracture. Methods From June 2021 to December 2021, medical records of 45 patients with femoral neck fracture treated with closed reduction and cannulated screws internal fixation were collected, including 25 patients with C-arm fluoroscopic-assisted internal fixation and 20 patients with orthopedic surgery robot 3D imaging system-assisted internal fixation. Gender, age, fracture Pauwels classification, time from injury to operation, operation time, intraoperative blood loss, guide pins drilling times, intraoperative duration of fluoroscopy (patients and doctors), number of fluoroscopy (patients and doctors), number of in-out-in of posterior screws, VAS score, Harris scores and fracture healing or not were compared between the two groups. Results In the C-arm fluoroscopy group, there were more times of guide pins implantation, longer time of doctors and patients fluoroscopy, more times of doctor fluoroscopy, higher VAS score at the last follow-up, and higher incidence of in-out in posterior and upper screw, while no screws in-out-in, the longer operation time and more fluoroscopy of patients were observed in the 3D imaging group. There was no difference in intraoperative blood loss and hip function between the two groups, and bone healing was observed at the last follow-up without postoperative complications. Conclusion The 3D imaging-assisted screws placement for closed reduction and internal fixation of femoral neck fracture has high accuracy, light postoperative pain and greatly reduced exposure to radiation, but there is a certain learning curve and longer operation time. In addition,compared with c-arm fluoroscopy, patients may absorb more X-ray radiation and attention should be paid