In this study, graphene nanoplate (GNP)-incorporated poly(vinyl alcohol) dense membrane was developed, characterized and used for selective separation of carbon dioxide from methane. The effects of graphene incorporation on crystallinity, mechanical strength, thermal degradation, morphology and CO2 gas separation performance of membrane were investigated. GNPs improved both mechanical and chemical properties of the membrane when the graphene concentration was below 1.5 wt%. The CO2 permselectivity of the membrane was also improved by graphene incorporation. The highest CO2 permeability of 81.45 Barrer and the highest CO2/CH4 ideal selectivity of 41.9 were achieved by using the 1.5 wt% graphene-loaded membrane.