The present invention relates to an organic luminescent material/clay nanocomposite with improved luminescent efficiency and stability, which is prepared by blending an organic luminescent material with a nanoclay, and an electroluminescent device employing the same. The electroluminescent device of the invention comprises: a transparent substrate; a semitransparent electrode deposited on the transparent substrate; a clay nanocomposite emissive layer spin-coated with an organic EL material/clay nanocomposite, positioned on the semitransparent electrode; and, a metal electrode deposited on the clay nanocomposite emissive layer. Since the electroluminescent device of the invention provides improved luminescent efficiency and stability, it can be practically applied to the development of organic semi-conductor.