A composition for a porous membrane of a secondary battery including a non-conductive particle and a water-soluble polymer, wherein the water-soluble polymer contains 80% by weight or more of a (meth)acrylamide monomer unit, and the water-soluble polymer has a storage modulus at 150° C. of 2.0×105 Pa or more; and a porous membrane manufactured therefrom and a secondary battery including the same.