In this paper MRF was prepared by ball wearing carbon-iron powder, sillocin oil or hydrocarbon oil, and additive. The MRF of high concentration and micron series was studied , the various properties and influence factors on MRF were analyzed. The results showed this method by mixing additive and improving compound technology could obtain a MRF with satisfactorily perfoemance. The car wisdom damper experiment showed this MRF was probably for using.