In this study, mixed matrix membranes (MMMs) are made based on polyurethane in combination with three different particles. Inorganic silica nanoparticle, Zeolite Socony Mobil–5 (ZSM-5) and Zeolitic Imidazolate Framework-8 (ZIF-8) were used as dispersed particles inside polyurethane matrix in order to separate two gases of carbon dioxide and methane. The distribution of suspension particle size in the solution is investigated by Dynamic Light Scattering (DLS). The effect of particle in polyurethane structure and the interaction between them are investigated by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM) analyses. In order to compare and investigate the effect of particles in the improvement of gases separation, MMMs were made with different weight percentage of the dispersed nanoparticles and were subjected to permeability test both in pure and in mixed gases of methane and carbon dioxide. Incorporation of silica nanoparticles within membrane causes the decrease of permeability and the increase of selectivity; while the behavior for the particles ZIF-8 and ZSM-5 were similar to each other and caused the increase of permeability and selectivity. The prepared polyurethane/ZIF-8 membranes showed the best separation performance, permeability 74.6 barrer and selectivity 19.1, because of better compatibility between ZIF-8 with polyurethane and proper sizes of pores. Finally, the composition of two gases was used at feed stream. In this condition, the amount of permeability was decreased similar to the selectivity of carbon dioxide.