Disclosed is a nanocomposite composition, comprising transparent nanoparticles, a matrix polymer including a polydimethylsiloxane resin and an epoxy group-containing polydimethylsiloxane resin, and a siloxane dispersant including a head part having an affinity for the transparent nanoparticles and a tail part having an affinity for the polydimethylsiloxane resin. The nanocomposite composition of this invention can be effectively used in the encapsulation layer of a light emitting diode or in an optical film.