The author reviewed 18 cases unstable pelvic bone fracture treated with Slatis trapezoid compression frame at the orthopaedic department of Capital Armed Forces General Hospital from May 1987 to February 1990. The results were obtained as follows:1. All patients were male, the peak incidence was in 3rd decade(83.2%) and the most common cause of injuries was traffic accident(55.5%). 2. The most common associated injuries were those of extremities followed by urogenital injury. 3. According to classification of Tile. Fourteen patients were type B and type C were observed in four patients. eleven patients were group II by Bucholz's classification, and seven patients were group III. 4. External fixation was applied in Tile type B, internal fixation or skeletal traction was applied combined with external fixation in Tile type C, A satisfactory result was obtained in 15 cases among the 18 cases. 5. Advantages of anterior external fixation for unstable pelvic bone fracture can be postulated as giving stability, early mobilization, rapid reduction of pain, easy care of associated injuries and reduction of pelvic hemorrage.