Objective      To study the effect of acetabular Center-edge (CE) angle and joint acting force direction on biomechanics of hip joint.     Methods      Three-dimensional hip joint models with different acetabular CE angles were established using computer-aided design (CAD) techniques according to the CT-scan images. Seven joint acting forces were loaded on the hip joint through the center of femur head from different directions. Stress on acetabular cartilage and displacement of femur head were studied by finite-element non-linear analysis.     Results      The average peak stress on acetabular cartilage increased to 7.89 MPa from 1.70 MPa

the distribution area of stress decreased gradually

and the distance from femur head displacement to the extra-hip joint increased to 2.88 mm from 0.04 mm when the acetabular CE angle was small. The vertical direction of joint acting force on hip joint with a smaller CE angle increased the peak stress on acetabular cartilage and the distance of femur head displacement.     Conclusion      CE angle and vertical acting force are the two important factors influencing the mechanics of hip joint.