Objective To investigate the factors that affect platelet-rich plasma (PRP) in promoting bone regeneration and repairing. Methods Recent l iterature was reviewed, concerning the preparations of PRP, physiological mechanism and the latest appl ications in orthopedic field. Results PRP, the concentrated body of autologous platelet, was rich in platelets and was the source of autologous growth factors. Many studies had shown that PRP played an important role in promoting bone regeneration and repairing. However, a few experimental results contradicted this point. The reason might be that the biological properties of PRP were influenced by various factors, such as workmanship, vector, activation schemes, working concentration, individual difference. Conclusion The concentration and qual ity of platelet and other related factorsof PRP affect the rel iabil ity of the results and conclusions. So an efficient and stable production method of PRP should beestabl ished.