The polysulfone mixed matrix membranes (MMM) with different concentrations of graphene oxide (0, 0.25, 0.5 wt.% polymer) fabricated by a phase separation method. The cross-sectional structure and their upper surface were assessed by (SEM) surface roughness of the membranes assessed by (AFM). The mechanical and thermal stability of the fabricated membranes evaluated as well. Carbon dioxide, nitrogen and methane separation from natural gas considered. An increase doping graphene oxide in matrix polymer outcome in a thicker sponge layer and disappearance of the finger-like cavities. From the outer surface morphology, the MMM presentation porosity a lower surface analogy the membrane neat. The membrane tensile strength and length of the membrane at fracture point increased slightly with an increase in graphene oxide concentration. transition Glass temperature membrane increased addition graphene oxide to the structure. From TGA analysis, in presence graphene oxide, thermal stability improved. From the gas permeation test, by addition of 0.25% graphene oxide to the polymer, CO2 permeability was increased from 61.22 GPU to 76.04 GPU, while addition of 0.5 wt.% resulted in a lower permeability (69.55 GPU). Nitrogen gas permeation flux of membranes decreased from 10.93 GPU to 3.91 GPU by addition of 0.50 wt.% of graphene oxide. Methane gas permeation flux is reduced from 11.31 GPU to 6.95 GPU and 4.92 GPU by addition of 0.25% and 0.50% graphene oxide, respectively. In conclusion, an increase in graphene oxide concentration increased carbon dioxide selectivity.