In a gas-barrier aluminum deposition film according to one embodiment of the present invention, a seed coating layer containing functional groups of at least one type selected from among a hydroxyl group (—OH), an amine group (—NH), and a carboxylic acid group (—COOH) is formed on a thermoplastic plastic base film to form a seed molecular layer that enables uniform deposition of aluminum, such as AlOx or AlNx, through chemical reaction, on a surface of the coating layer, with aluminum atoms vaporized at the initial stage of aluminum deposition, thereby inducing uniform deposition of an aluminum layer to be subsequently deposited. Therefore, it is possible to provide a deposited film having superior oxygen and water vapor barrier properties compared to existing aluminum deposition films.