ObjectiveTo review the recent research progress of the regulatory mechanisms of osteoclast (OC) formation and functions. MethodsThe related literature on OC formation, activation, and functions was reviewed, analyzed, and summarized. ResultsMacrophage colony stimulating factor and receptor activator of nuclear factor-κB ligand are essential cytokines which regulate all aspects of OC formation and functions. In additional to mediating bone resorption, OCs also partici pate in regulation of osteoblast formation and immune responses. ConclusionThe researches on the regulation of OC formation and functions have further revealed the destruction mechanisms of various kinds of bone diseases, which will facil itate to find more suitable biological targets for cl inical therapy.