The invention discloses an organic electroluminescent device which comprises the components of an anode conductive substrate, an organic light emitting functional layer, a cathode and a packaging layer; wherein the organic light emitting functional layer, the cathode and the packaging layer are successively laminated on the anode conductive substrate. The packaging layer comprises a first inorganic barrier layer and a second inorganic barrier layer which are successively laminated on the surface of the cathode. The first inorganic barrier layer is made of bromine-doped titanium oxide, bromine-doped zirconia, iodine-doped titanium oxide, iodine-doped zirconia or iodine-doped hafnium oxide. The second inorganic barrier layer is made of silicon oxide, alumina, titanium oxide, zirconia, hafnium oxide, tantalum oxide, silicon nitride, aluminum nitride, boron nitride, vanadium nitride, tantalum nitride or titanium nitride. The packaging layer of the invention has high compactness, thereby prolonging service life of the organic electroluminescent device, particularly a flexible organic electroluminescent device. The invention further provides a preparation method for the organic electroluminescent device.