Nowadays, the development of high barrier polymer film has been a long-standing issue in the packaging industry due to the low effectiveness of single polymer film in preventing oxygen-sensitive commodities degradation. It is well established that polymer nanocomposite obtained by incorporating nanoplatelets into a polymer matrix seems to be a versatile strategy for fabricating high barrier polymer films, where the enhanced gas barrier performances principally depend on the volume fraction of the nanoplatelets, their orientation relative to the diffusion direction and their aspect ratio. Recently, graphene oxide nanosheets (GONSs) are well behaved as outstanding candidates to advance gas barrier properties of polar polymer films thanks to their unique graphitized planar structure, extremely high specific surface areas, large aspect ratios, as well as the abundant oxygen-containing functional groups on their basal planes and edges. In the present work, the high orientation and random distribution of the well-dispersed GONSs were respectively designed in the poly(vinyl alcohol) and poly(lactic acid), in which the barrier properties of the as-prepared nanocompoiste films were improved by a large margin at a low GONS loading. Apparently, GONSs could be viewed as “nano-barrier wall” for the diffusing molecules, resulting in a significant decline in diffusion coefficient. This effect has been widely carried out to clarify the transport properties of nanoplatelet/polymer nanocomposites. The contribution of solubility coefficient to enhanced barrier properties, however, is normally neglected or underestimated. Herein, we preliminarily explored the importance of solubility coefficient in reducing gas permeability coefficient by the deviation between experimental data and simulative curves. And ongoing work should to be conducted to further investigate the influence of interfacial region in the nanocomposite films on their barrier properties.