Abstract:[Objective] To explore the clinical outcomes of the anterior locking plate for internal fixation of acetabular fractures involv- ing quadrilateral area. [Methods] A retrospective study was done on 32 patients who received open reduction and internal fixation (ORIF) for acetabular fractures involving quadrilateral area in our hospital from January 2017 to December 2020. Based on Letournel-Judet classi- fication, 6 patients were of anterior wall combined with posterior semi-transverse fractures, 7 were of transverse fractures, 12 were of dou- ble-column fractures and 7 of T-shaped fractures. All patients had fractures fixed with anterior locking plate combined with the reconstruc- tion plate through the lateral rectus approach. The clinical and radiographic documents were summarized. [Results] All patients had ORIF performed smoothly without iatrogenic injury to blood vessels and nerves, and followed up for 12~41 months, with an average of (25.84± 10.95) months. The patients resumed full-weight bearing activity in (11.93±3.62) weeks on average, and got significant increases of hip flex- ion-extension and internal-external rotation range of motions (ROM) over time. According to Merled' Aubigné-Postel criteria, the clinical outcomes were marked as excellent in 22, good in 6, fair in 3 and poor in 1, with excellent and good rate of 87.50% (28/32) . In term of Mat- ta criteria, anatomic reduction achieved in 23 cases (71.88%) , satisfactory reduction was in 7 cases (21.88%) and unsatisfactory reduction was in 2 cases (6.25%) , with total satisfactory rate of 93.75% (30/32) . To the latest follow up, all the patients got fracture healing without adverse imaging findings, such as heterotrophic ossification, femoral head necrosis and implant loosening. [Conclusion] The anterior lock- ing plate for internal fixation of acetabular fractures involving the quadrilateral area is reliable technique to achieve satisfactory clinical out- comes.