Sulfonic acid-based membrane gives the relatively high conductivity only in the presence of water, but phosphoric acid-based membrane presents the relatively high proton conductivity without water because of its self-dissociation natures to develop high temperature PEMFCs. We synthesized the membrane that has phosphorous groups based on poly(dimethyl siloxane) (PDMS). PDMS, which is intrinsically hydrophobic, was modified to be amphiphilic by substituting end groups with hydrophilic phosphorous groups. And we used porous poly(tetra-fluoroethylene) film (POREFLON) for improved mechanical properties of membranes. The membranes maintained the constant proton conductivity above 130 degrees C under dry conditions. This membrane may be used as high temperature PEMFCs at low humid conditions.