In this study, nano-pores in cellulose acetate matrix were generated by utilizing glycerin with water pressure without metal salts as additive. When cellulose acetate polymer membrane fabricated with glycerin as an additive was exposed to water pressure as external physical force, nano-pore generation depends on the pressure-strength exerted on the membrane. On the principle of the nano-pore generation, the chains became weakened in the portion of the cellulose acetate, in which glycerin was surrounded by abundant water molecules, resulting in plasticization capable of easily generating nano-pores with water pressure. We found that pore size and numbers of nano-pore could be easily controlled by adjusting the water pressure. Thus, we succeeded in preparing the porous cellulose acetate with high porosity of 78.3%.Generated pores in cellulose acetate polymers were confirmed by scanning electron microscopy (SEM) images and porosimeter. The coordinate interactions between cellulose acetate (CA) polymers and glycerin were investigated by FT-IR and TGA analysis.