Objective To investigate the cl inical effect of the acetabular tridimensional memoryalloy-fixation system (ATMFS) in treatment of posterior wall acetabular fractures with posterior dislocation of hip. Methods From January 2004 to February 2006, 15 cases of posterior wall acetabular fracture with posterior dislocation of hip were treated. There were 11males and 4 females, aged 21-68 years old with an average of 43.5 years old. Injury was caused by traffic accident in 8 cases, by fall ing from height in 5 cases and others in 2 cases. The locations were the left hip in 9 cases and the right hip in 6 cases. According to Thompson-Epstein’ fracture classification, there were 6 cases of type II, 5 cases of type III, 2 cases of type IV and 2 cases of type V. Imaging showed the acetabular articular surface displacement of 2-5 mm(mean 3 mm). The time from injury to hospital ization was 6 hours to 2 weeks(mean 1.5 days). Skeletal traction on femoral condyle was given, manual reduction was performed in 12 patients and intra-operative reduction in 3 cases. ATMFS was used after 2-7 days of hospital ization, and 4 cases received autologous free il ium because of bone defect. Results The operative time was 90-390 minutes with an average of 210 minutes. Intraoperative blood loss was 350-2 500 mL with an average of 360 mL. The hospital ization days of the patients ranged from 7 to 21 days(mean 10 days). Epidermal infection occurred and was cured after symptomatic management in 1 case. Other incisions healed by first intention. No deep infections, pulmonary embol ism, deep venous thrombosis and other compl ications occurred. The patients were followed up 1 to 3 years with an average of 1.6 years. Ischemic necrosis of femoral head occurred in 1 case. Heterotopic ossification in grade II occurred in 1 case. The hip function was still good without special treatment. According to Matta’s X-ray fracture reduction assessment, the results were excellent in 7 cases, good in 5 cases, fair in 2 cases, and poor in 1 case, the excellent and good rate was 80%. According to d’Aubigné cl inical efficacy evaluation, the results were excellent in 8 cases, good in 5 cases, fair in 1 case, and poor in 1 case, the excellent and good rate was 86.7% at last followup. Conclusion ATMFS can be used for the treatment of posterior wall acetabular fracture with posterior dislocation of hip, which can improve the anatomy corresponding rate of the femoral head and reduce the incidence of compl ications and restore the function of the hip.