Abstract: [Objective] To analyze the clinical efficacy of a novel assisted reduction fixation device in the operation of the supracondylar humerus fracture in children. [Methods] A retrospective study was conducted in 85 patients who underwent closed reduction and percutaneous pinning surgeries in our hospital from June 2019 to June 2022. Forty-three patients treated with a new assisted reduction fixation device to assist in closed reduction and percutaneous K-wire needle cross-fixation were allocated into study group, and 42 patients with traditional closed reduction and percutaneous K-wire needle cross-fixation were assigned into control group. The operation duration, intraoperative fluoroscopy frequency, Baumann angle, carrying angle, fracture healing time and Flynn score of elbow joint function at the final follow-up were compared between two groups. The postoperative complications of two groups were recorded. [Results] There were significant differences between two groups in terms of operation duration, intraoperative fluoroscopy frequency, and carrying angle (p<0.05), while no significant differences of Baumann angle and the fracture healing time between two groups were observed (p>0.05). In the control group, ulnar nerve injury in one case, needle site infection in 2 cases and mild cubitus varus in 2 cases were detected. In the study group, delayed ulnar nerve palsy in one case was observed. There was no significant difference in Flynn scores between two groups. [Conclusion] The novel assisted reduction fixation device is simple and convenient. Closed reduction and percutaneous K-wire needle cross-fixation with this device has similar effect to traditional treatment of supracondylar humerus fracture in children. The application of the novel device could relatively shorten the operation duration and reduce the intraoperative fluoroscopy frequencies.