To study a method of in vitro preparation and seperation for metallic wear particles around joint prosthesis, and evaluate its feasibility in medical experiments of prosthetic loosening.Preparation of Metallic Wear Particles Around Joint Prosthesis by Vacuum Ball Mill in Vitro .Particle size,size distribution,chemical composition,and shape were characterized by element trace analysis, laser countersizer,scanning electron microscopy. Metal particles co-culture with RAW264.7,then detect cytotoxicity.Our metal particles that prepare by vacuum ball mill that closely resembled particles found around solid and loose human prostheses(＜5μm in diameter).The addition of metal particles（＜1.0 mg/ ml in concentration) to RAW264.7 co-culture did not cause cell cytotoxicity，and we can use it in relative research of Cytology.This method is good enough to produce metallic wear particles that closely resembled particles in vivo, which has convenient ,reproducibility. and can be used in vitro studies of Cytology.