A method for forming a thin film and a method for fabricating a liquid crystal display device using the same are provided. The method provides a process that is simplified. Uniform thin film characteristics can be obtained. The method for forming a thin film includes the steps of forming a diffusion barrier film on a substrate, forming a metal seed layer on the diffusion barrier film, removing a metal oxide film formed on a surface of the metal seed layer using an electric plating method, and depositing metal on the metal seed layer in which the metal oxide film is removed.