A device for attaching a decorative film to a surface of a 3D glass, includes a vacuum chamber, an upper mould, and a lower mould. The upper mould includes an upper planar pressing portion and an upper curved portion. The lower mould includes a lower planar pressing portion and a lower curved portion, the upper planar pressing portion and the lower planar pressing portion are configured to correspond to a planar portion of the 3D glass, the upper curved portion and the lower curved portion are configured to correspond to a curved portion of the 3D glass, the upper mould is provided with a first heating block. The present disclosure further discloses a method thereof.