Abstract: To evaluate the cementless fixation of pearl surfaced hip prosthesis,experiment was performed in 33 mongrel dogs.Histomorphological and biomechanical studies verified the new bone occurred in two weeks and all the prostheses were well fixed by bony ingrowth from one monthes on after implantation.On the basis of the experimental results 49 pearl surfaced total hip arthroplasties were carried out from Sept,1983 to Mar,1986.The preliminary following-up observation were excellent.