Objective To explore the clinical effect of elbow arthrography through lateral approach in assisted treatment of Monteggia fracture in children. Methods A retrospective analysis was performed on the clinical data of 54 children with Mengzi fracture treated in The Affiliated Hospital of Chifeng University from June 2009 to June 2020. According to whether elbow arthrography was performed, the patients were divided into contrast group (n=24) and non-contrast group (n=30). The operation time, fluoroscopic times, hospitalization cost, Postoperative VAS score, fracture healing time, clinical efficacy and complications of the two groups were analyzed and compared. Results The operation time and the times of fluoroscopy in the contrast group were significantly less than those in the non-contrast group (P＜0.05). There were no significant differences between the two groups in hospitalization cost, postoperative VAS score, fracture healing time, elbow flexion and extension range of motion and forearm rotation range of motion and clinical efficacy (P＞0.05). One patient in each of the two groups had symptoms of Kirschner wire tail irritation, which disappeared after being pulled out. There were 2 cases of premature closure of the epiphysis and 1 case of re-dislocation of the radial head in the non-contrast group, while no premature closure of the epiphysis and re-dislocation of the radial head occurred in the contrast group. There were no incision infection, nerve injury, fracture malunion, necrosis of radius head, joint stiffness, myositis ossificans, and no adverse reactions such as contrast agent allergy. The incidence of complications in the contrast group was significantly lower than that in the non-contrast group (P＜0.05). Conclusion The application of elbow arthrography through lateral approach in assisted treatment of Monteggia fracture in children, in addition to saving operation time, reducing radiation, it can also reduce complications without increasing postoperative pain and economic burden of patients, and without affecting fracture healing and clinical effects.