Fluorine modified diisocyanate(FMD) was synthesized from Tris(6-isocyanatohexyl)isocyanurate(TIHI) and N-ethyl-N-2-hydroxyehtyl-perfluorooctanesulfonamide(HFA). Fluorine modified polyurethane(FMPU) was also synthesized from FMD and poly(tetramethylene) glycol(PTMG). Modified polyurethanes were made by blending FMPU into the polyester type base polyurethane(BPU) and surface energy was calculated from contact angles. When molecular weight of PTMG was 1,000, surface energy of FMPU was smaller than molecular weight of FMPU was 2,000. This result showed that surface properties of FMPU were effected molecular weight of polyols.