e measured. The fracture surface morphologies were observed and analyzed by SEM. The results indicate that rare earth elements can effectively promote the interfacial adhesion between the glass fiber and PTFE, owing to the effects of rare earth elements on the compatibility. The tensile properties of GFPPTFE composites can be improved considerably when the content of RE in surface modifier is 0.2 %～014%, and the optimum performance of GFPPTFE composites is obtained at 0.3 %RE content.