Polylactic acid (PLA) is a kind of biopolymer made from non-conventional resources. It is biodegradable and has high mechanical properties. However, its use as the packaging material in the food-packaging sector is limited due to its brittleness and porosity. Therefore, to reduce the brittleness and improve the barrier properties, the compression-molded PLA/ESO films were surface treated with N2 plasma. Water vapour permeability, migration and differential scanning calorimetry tests have been carried out to assess the surface barrier performance and thermal properties of the manufactured films. The surface-treated PLA/ESO showed better barrier properties than pure PLA and PLA/ESO. The water vapor transfer rate of surface-treated PLA/ESO was 3.35 % lower than the PLA/ESO. The improvement in barrier properties, as well as the reduction in glass transition temperature, could increase the potential of the material for packaging.