Objective To evaluate the applicable and clinical value of CT and radiography in the dignosis of acetabular fractures.Methods The data of CT,X-ray and clinical treatment in 18 cases with acetabular fractures were analyzed and comparatively.Results There were 4 cases of the anterior wall fracture,4 cases of the anterior column fracture,2 cases of the posterior wall fracture,2 cases of the posterior column fracture and ,6 cases of complex fracture,11 cases were in company with swelling of the soft tissue in pelvic cavity.Of them,4 cases misdiagnosed by radiography.27 pieces of bone fragment were detected by CT,including 17 pieces of them in joint cavity.12 pieces of bone fragment were detected by X-ray,only 4 pieces of them were in joint.3 cases with femoral head fracture were included in 7 cases of the hip joint dislocation,1 case of them was misdiagnosed by X-ray.Conclusion In detecting the bone fragments in articular space,the type of acetabular fractures and soft-tissue swelling,CT is super to radiography.