Abstract: The wear mechanisms of two kind Kevlar fiber reinforced phenolic resin frictional materials were investigated by scanning electron microscopic observation of the worn surface morphologies and energy dispersive X ray microanalysis of the compositions of the worn surfaces. As the results, the two kind frictional materials in sliding against cast iron counterpart show signs of adhesion wear and plastic deformation. The plastic deformation is accelerated at high sliding speed and normal load, which is accompanied by localized melting on the worn surfaces of the frictional materials. The inter transfer between the frictional materials and the cast iron counterpart is also observed and a transfer film of the frictional materials is formed on the counterpart surface. It is easier for the transfer films of the frictional materials to form at higher sliding speed and normal load. Kevlar fiber as the reinforcing agent helps to stabilize and lower the friction coefficient. The frictional materials is characterized by slight scuffing, adhesion, and plastic deformation, in sliding against the cast iron counterpart.