Abstract: An unidirectional nanopore dehydration-based functional polymer membrane or hydrogel membrane, preparation method thereof and device thereof. Adding an aqueous polymer solution or a polymer mixture solution into a mold through a sampling hole on the top of a container with a nanoporous filter film as the bottom, after closing said sampling hole, the water molecules in the solution are dehydrated in one direction downward through the nanopores of the filter film, and obtain said polymer membrane or hydrogel membrane on the upper surface of the nanoporous filter film; it can also undergo in situ polymerization with pyrrole in an aqueous solution to obtain a conductive PM or PHM modified by polypyrrole. The invention adopts a UND-based mold, and green processing obtains a novel polymer material with an ordered molecular arrangement, which has the characteristics of flexibility, transparency, and robust mechanical properties. The polymeric material has broad applications.