Objective To investigate the morphological characteristics of the posterior acetabular column and the femoral head by three-dimensional reconstruction models for providing an anatomical basis for intraoperative plate molding and the development of anatomical plate of the posterior acetabular column.Methods Three-dimensional reconstruction models of the pelvis were established based on CT scan data of 111 adult patients,including 72 males and 39 females,aged from 18 to 80 years (average,45.4 years).According to the models,the femoral head diameter was tneasured; along the posterior acetabular column plate path,three approximate arcs with a corresponding radius of curvature (R1,R2 and R3) were created to fit the posterior wall,proximal end and distal end of the acetabulum.The angle α,which reflected the relative position between the three arcs,was recorded.Results The average femoral head diameter,R1,R2,R3 and angle α was 47.43±3.74 mm,47.96±7.80 mm,67.71±13.35 mm,9.76±0.43 mm and 51.38°±6.83°,respectively.There was statistical difference in femoral head diameter and angle α between females and males (t=12.37,P=0.00; t=2.63,P=0.01),while no statistical difference was found in R1,R2 and R3 between them (t=1.05,P=0.30; t=1.36,P=0.18; t=0.72,P=0.47).There was a positive correlation between the femoral head diameter and angle α (r=0.37,P=0.00),while no correlation was found between the femoral head diameter and R1,R2 and R3 (r=0.09,P=0.34; r=0.08,P=0.43; r=-0.00,P=0.98).R2 increased with R1,while angle α decreased with increase of R1 and R2,and R3 was independent with a little variation.Conclusion The morphology of the posterior acetabular column has variances among individuals,with no obvious correlations with femoral head diameter and gender.The radian of posterior acetabular wall determines the shape of the posterior acetabular column plate.