Micropours polymeric membranes were prepared from homogeneous solution of Polysulfone (PSF) by phase inversion method. Nmethyl-2-pyrrolidone (NMP) was used as solvent. Polyethylene glycol (PEG) (average molecular weight 6000) was used as the polymeric additive in different concentration in the casting solution. The morphology and structure of the resulting membranes were observed by scanning electron microscope (SEM).The permeation performances of the membranes were evaluated in terms of equilibrium water content (EWC) and Porosity. Thermal and mechanical properties of membranes were analyzed by differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) and a universal mechanical testing machine.Results showed that with increase in concentration of PEG, the pore number as well as average pore size in membranes increases. Membrane with PEG of (5wt. %) has higher (EWC) and porosity due to high porosity.