Poly(vinylidene chloride) (PVDC)-based carbon with high microporosity was prepared via facile carbonization, and further moderate KOH activation can widen micropore size with higher surface area and larger pore volume. A superior CO2 capture uptake at 1bar of up to 5.87mmol/g at 0°C and 3.98mmol/g at 25°C is obtained for pristine carbon and the isosteric heat of CO2 adsorption is in the range of 24–28kJ/mol, along with fast kinetics. The KOH activated sample shows a slightly low CO2 uptake at 1bar because activation produces some larger micropores in frameworks, resulting in the reduction of interactions between pores and CO2 molecules.