High-speed railway polyurethane (PU) shock was prepared with 4,4′-diphenylmethane diisocyanate (MDI) and polyether polyol. The effects of kinds and amount of chain extender on molding and properties of high-speed railway shock were investigated. The results show that with increase of the amount of chain extender, the reaction speed and the tensile strength, dynamic mechanical property, the heat resistance are increased, the elongation at break is decreased, the product property of static stiffness is increased, the dynamic-static stiffness ratio is increased first then decreased. In addition, with increase of the length of molecular chain of different kinds of chain extender, except for 1,3-butanediol, the material properties of tensile strength, oil resistance are decreased, the elongation is increased first and then decreased, the low temperature resistance and compression set are improved, the static stiffness rises up, the dynamic-static stiffness ratio is reduced.