Objective: To report and assess the efficacy of a coupled exofixator in the treatment of comminuted fracture of the humeral shaft.Methods: From June 1999 to September 2003, 24 patients with comminuted fracture of the humeral shaft were treated in our department, in whom 11 were involved in left humerus fractures and 13 in right humerus fractures. Closed reduction or open reduction with a small incision as well as a coupled exofixator was used to treat these patients. Results: All cases got anatomical reduction after 6-12 months follow-up. The time for fracture union averaged 5.8 months with a good functional recovery of the shoulder-elbow joints. Conclusions: The coupled exofixator is favorable to the treatment of comminuted humeral shaft fractures. It can shorten union time and avoid nonunion occurrence.