Provided in the invention is an organic light-emitting device comprising a substrate, an
anode, a functional layer, a
cathode, a packaging layer, and a packaging cover. The substrate, the
anode, the functional layer, the
cathode, the packaging layer, and the packaging cover are successively laminated. The substrate and the packaging cover form an enclosed space; and the
anode, the functional layer, the
cathode, and the packaging layer are accommodated into the enclosed space. The packaging layer successively includes a
protection layer, an
oxygen-
nitrogen compound film, an organic
blocking layer, a
moisture absorbing layer, and a cooling layer; and the
oxygen-
nitrogen compound film is an
oxide film doped with
nitride. In addition, the invention also provides a preparation method of the organic light-emitting device. With the method,
erosion on the organic light-emitting device by
moisture and
oxygen can be effectively reduced, so that the device organic functional material and the
electrode can be effectively protected and thus the service life of the organic light-emitting device can be obviously prolonged. The method is especially suitable for packaging of a flexible organic light-emitting device.