Objective:The design and initial stability of threaded acetabular prosthesis was studied in this paper. Method: The initial stability of threaded acetabular component was tested on the biomechanical test system. The threaded cup was fixed by direct rotation, the control group smooth acetabular cup was fixed with three cancellous screws. The forces moving prosthesis 100μm were tested at three direction of axial, clockwise and anti-clockwise. Results: The study shows that the threaded acetabular prosthesis has excellent initial stability with significant difference in statistics and provide theoretical basis for this prosthesis applied in clinical practice.