Activated carbon nanofibers were prepared with polymer blends that consisted of polyacrylonitrile (PAN) and cellulose acetate (CA), by electrospinning and subsequent thermal treatment. The average fiber diameter of samples was about 200 nm, ranging from 150 to 400 nm. The specific surface area, total pore volume, and micropore volume increased with increasing CA content. As the CA content was increased up to 20%, the pore characteristics for the adsorption performance were enhanced. However, excess CA content (over 30%) was harmful to volatile organic compounds (VOCs) adsorption ability due to changing morphology of the activated carbon nanofibers. The O/C ratio was increased with increasing CA content. However, the O/C ratios of all activated carbon nanofibers prepared with blends represent small values revealing non-polarity of the surface. The adsorption capacities of PC10, PC09, PC08 and PC07 were 65 g/100 g, 66 g/100 g, 72 g/100 g and 67 g/100 g. The blends of the PAN with CA showed better characteristics than those of PAN alone, but apparently there is an appropriate blending ratio (20%) for high-performance of activated carbonaceous materials.