The present invention relates to a nanocomposite blend composition having superior barrier properties, and more particularly to a nanocomposite blend composition comprising a polyolefin resin; one or more nanocomposites having barrier properties, selected from an ethylene-vinyl alcohol (EVOH)/intercalated clay nanocomposite, a polyamide/intercalated clay nanocomposite, an ionomer/intercalated clay nanocomposite, and a polyvinyl alcohol (PVA)/intercalated clay nanocomposite; and a compatibilizer. This nanocomposite blend composition has superior mechanical strength and superior barrier properties to oxygen, organic solvent, and moisture. Also, it has superior chemical barrier properties and is applicable to single/multi-layer blow molding and film processing.