Porous hydrophobic poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hollow fiber membranes were prepared via a wet spinning process using polyethylene glycol (PEG-400) and ortho-phosphoric acid (PA) in the spinning dope. CO2 stripping from diethanolamine (DEA) solution was conducted through the gas–liquid membrane contactor modules. By obtaining cloud point diagrams, higher phase inversion rate was confirmed for the solution with PA. The smaller finger-like macrovoids were resulted when using the non-solvent additives. The membranes with higher surface porosity and smaller mean pore size were produced when using the additives in the spinning dope. The improved PVDF-HFP/PA membrane had the mean pore size of 0.015µm and permeability of 13,100GPU. This membrane showed a minimum mass transfer resistance of 15,982 (m/s)−1 which is about 68% less than the resistance of plain PVDF-HFP membrane. The improved PVDF-HFP/PA membrane showed CO2 stripping flux of about 9 × 10−3mol/m2s at the liquid velocity of 0.045m/s.