Objective To investigate the curative effects of open reduction and internal fixation with Kirschner wire for Mason type-II radial head or neck fracture in children. Methods From September 2007 to June 2009, 17 cases of Mason type-II radial head or neck fracture were treated, including 11 males and 6 femals with an average age of 8.5 years (4-11 years).The locations were left side in 5 cases and right side in 12 cases. All fractures were caused by fall ing and classified as Mason type- II fracture. Two cases compl icated by radial nerve deep branch injury. The time from injury to operation was 4 hours to 5 days. All cases received open reduction and internal fixation with Kirschner wire. They were evaluated by anteroposterior and lateral radiographs and functionally by Broberg criteria. Results Wound healed primarily in all patients. According to Métaizeau criteria, the results were excellent in 15 patients and good in 2 patients, who achieved anatomical reduction. Seventeen patients were followed up for a mean time of 14 months (6-25 months). Function returned to normal in 2 cases compl icated by radial nerve deep branch injury after 6 months of operation. No compl ications of infection and nerve injury occurred. The X-ray films showed that bony heal ing was achieved in all cases; the heall ing time was 2.0-3.5 months (mean 3 months). According to Broberg criteria, the outcome was excellent in 11 cases, good in 4 cases, and fair in 2 cases, the excellent and good rate was 88.2%. Conclusion Open reduction and internal fixation with Kirschner wire has good effect, satisfactory functional recovery and less compl ication in the treatment of Mason type-II fracture of radial head or neck in children.