Objective: To investigate the application effect of electric drill drive in the preparation of atlanto-axial posterior screw trajectory. Methods: A retrospective case-control study was conducted to analyze the clinical data of 29 patients with atlanto-axial fracture and dislocation admitted to the Lanzhou University Second Hospital from February 2016 to March 2019. There were 19 male and 10 females, aged from 10 to 72 years, with an average of 44.6 years. All patients received posterior atlantoaxial screw fixation. Electric drill drive was adopted in 14 patients to prepare the screw trajectory (electric drill group), and bare hand technique was used in 15 patients (bare hand group). In the electric drill group, 28 atlantal lateral screws and 28 axial pedicle screws were implanted; in the free hand group, 30 atlantal lateral screws and 30 axial pedicle screws were implanted. The trajectory preparation time and intraoperative blood loss between the two groups were compared. After the operation, the X-ray films and 3D CT were taken to observe the lateral mass of atlas as well as the position, loosening or rupture, and bone healing of axial pedicle screws, and complications. Frankel grading and visual analogue scale (VAS) at the last follow-up were compared between the two groups. Results: All patients were followed up for 3 to 36 months, with an average of 21 months. The electric drill group took significantly shorter time in preparing both atlantal and axial pedicle screw trajectories than the bare hand group [(8.8±4.2)minutes ∶(16.5±9.7)minutes; (4.1±1.2)minutes∶ (6.1±3.2)minutes] (P<0.05). There was no significant difference in intraoperative blood loss between the electric drill group and the bare hand group [(54.2±32.0)ml ∶ (58.0±28.4)ml] (P>0.05). In the electric drill group, the penetration rate of atlantal screws was 0, the complete position rate was 96% (27/28), and the good rate of screw placement was 100% (28/28), superior to 23% (7/30), 73% (22/30) and 73%(22/30) in the bare hand group (P<0.05). In terms of the axial screws, in the electric drill group, the panetration rate was 4% (1/28), the complete position rate was 82% (23/28), and the good rate of screw placement was 96% (27/28), superior to 10% (3/30), 70% (21/30) and 93% (28/30) in the bare hand group (P>0.05). There were no complications such as cerebrospinal fluid leakage, spinal cord injury, cerebellar infarction, loosening and fracture of internal fixation, and nonunion of bone. At the last follow-up, Frankel grading and VAS of the two groups were improved to different degrees (P<0.05), but there was no significant difference between the two groups (P>0.05). Conclusion For atlantoaxial fracture and dislocation, preparation of atlantoaxial internal fixation screw trajectories by electric power can significantly shorten the operation time and improve the accuracy of atlas screw placement.