Synoviocyte is one of the cells in direct contact with the wear particles and the role of synoviocytes in the prosthesis loosening remains to be further understood. The purpose of the present study is to investigate whether particulate biomaterials cause synoviocyte dead or simply activate these cells. The activation of synoviocyte in response to particulate biomaterial exposure will be indicated with its phagocytotic ability. As to the effects of particulate biomaterials to apoptosis will be tested on rabbit synoviocytes, HIG-82 cells. The results demonstrate that the addition of cobalt particles would lead the HIG-82 cells to apoptosis and apoptosis accompanying caspase3 cleavage, which means that apoptosis of the HIG-82 cells resulted from the addition of cobalt particles might went through caspase-dependent pathway. On the other hand, exposing to nonmetal particles such as TiO2 and SiO2, particles did not provoke apoptosis of the HIG-82 cells. TiO2 particles activated the cells and were phagocytosed by the HIG-82 synoviocytes, no significant biological effects were found while the HIG-82 cells exposed to SiO2 particles.