Provided are a nanocomposite including a layered inorganic material and a random copolymer containing a hydrophobic monomer and a hydrophilic monomer, a polymer composition including the nanocomposite, and a method for preparing the polymer composition. The random copolymer can be prepared at a low cost in a simple process and function as a compatibilizer in small amounts to maintain excellent properties of the nanocomposite including excellent mechanical characteristics such as abrasion resistance, hardness, tensile modulus and tear resistance, excellent thermal characteristics, high liquid and gas permeability, and low flammability.