A multi-layer thin film for encapsulation and the method thereof are provided. The multi-layer thin film for encapsulation includes a protective layer composed of aluminum oxide, a single or double barrier layer composed of silicon nitride (SiNx), and a mechanical protective layer composed of silicon dioxide (SiO2). The multi-layer thin film can be economically fabricated by using the existing equipment, and has a high level of light transmission over 85% while showing a low level of oxygen and moisture penetration. Additionally, due to superior adhesive strength between the thin films, and high resistance against impacts by heat or ion during a fabricating process, reliability of fabrication is enhanced, and it can thus efficiently used in encapsulating an organic light-emitting device (OLED), a flexible organic light emitting device (FOLED) in a display field, and the cells such as a thin film battery and a solar cell.