Artificial joints are made of metal and polymer (plastic) or inert materials (ceramic). Its structure and appearance are close to the anatomical form of the human body. Since the artificial joint is to be implanted in the human body for a long time, the material requirements are non-toxicity, non-irritation, good histocompatibility, good mechanical properties, wear resistance, and sufficient strength. Different parts of the artificial joint are designed according to the morphology and function of the original joint. In the case of the hip joint, there are artificial femoral head, acetabular cup, femoral stem, the head and stem have metal composition; the cup has ultra-high polymer polyethylene-made (artificial head can also have ceramic production). Currently, the metals are cobalt-chromium-molybdenum and titanium alloys.