OBJECTIVE: To compare clinical effect of Kirschner wire radial sector fixation and bilateral ulnar radial cross fixation in treating supracondylar fracture of humerus in children after closed reduction. METHODS: From March 2017 to December 2018, 60 children with supracondylar fracture of humerus treated with closed reduction and Kirschner wire fixation were analyzed retrospectively, and divided into two groups according to different needling methods. Thirty patients in radial three needles fan fixation group (group A), including 19 males and 11 females, aged from 2 to 10 years old with an average of (5.00±2.10) years old, 21 patients were typeⅡ and 9 patients were typeⅢ according to Gartland classification. Thirty patients in cross fixationwith 3 needles on both ulnar and radial side group(group B), including 22 males and 8 females, aged from 1 to 9 years old with an average of(5.13±2.08) years old, 19 patients were typeⅡand 11 patients were typeⅢ. Healing time of fracture, postoperative complications, elbow flexion and extension activity, forearm rotation activity recovery, elbow carrying angle and angle loss after operation between two groups were observed and compared. Mayo Elbow function score at the final following up was used to evaluate clinical efficacy. RESULTS: All patients were followed up, while there were no significant difference in follow-up time and fracture healing time between two groups (P>0.05);there was 1 patient occurred iatrogenic ulnar nerve injury in group A, 9 patients in group B, and there was difference between two groups (P<0.01);2 patients in group A occurred mild displacement and 1 patient in group B, while no significant difference between two groups(P>0.05). No cubitus varus deformity, needle infection, osteofascial compartment syndrome and myositis ossificans occurred. There was no significant difference in elbow flexion, extension activity, and forearm rotation activity between two groups at 3 months after operation(P>0.05); there was no significant difference in elbow carrying angle and its loss angle between two groups at 3 and 6 months after operation (P>0.05);there was also no significant difference in Mayo Elbow function score and efficacy evaluation at the final follow-up (P>0.05). CONCLUSION: Closed reduction and Kirschner wire at the early stage of fracture has advantages of less trauma, easy reduction, stable fixation, and early functional exercise. The risk of iatrogenic ulnar nerve injury caused by fan-shaped fixation of three radial needles is less than that of cross fixation of three radial needles.