Sulfur dioxide (SO 2 ) is the major air pollutant which is emitted from the power plant. In this study, hollow fiber membrane (HFM) separation process is applied for the improvement of SO 2 removal efficiency in the post-combustion gas. HFM was produced by dry/wet phase inversion method and then coated with Polydimethylsiloxane (PDMS). The membrane morphology and characterization were examined with help of scanning electron microscope (SEM), energy dispersion of X-ray spectroscopy (EDX), Fourier transform infrared (FT-IR) and atomic force microscopy (AFM). Polyethersulfone (PES) hollow fiber membranes were tested for the SO 2 /N 2 binary mixed gas separation. Single gas permeance of SO 2 , N 2 , and binary mixture gas (200 ppm of SO 2 ) separation experiment was initiated to observe membrane behavior according to temperature and pressure difference and retentate flow rate. As a result, permeance of SO 2 was 24.9-47.4 GPU and selectivity of SO 2 /N 2 was 1.6-4.2. From the mixture gas separation experiment, SO 2 removal efficiency increased according to stage cut and operating pressure.