A series of mixed matrix membranes (MMMs) were fabricated with Ni-MOF-74 as filler and poly (styrene-b butadiene-b-styrene) (SBS) polymer as matrix materials for CH4/N-2 separation. MMMs were characterized by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Gas separation behavior was investigated by measuring single and mixed gases. For the single gas, the CH4 permeability of the MMMs incorporated with 15 wt% Ni-MOF-74 (Ni-MOF-74/SBS-15) reached 83.5 Barrer, which was 116% higher than that of SBS (38.6 Barrer), while its ideal selectivity remained the same. CH4 permeability can further increase to 176.6 Barrer with the increase in temperature to 55 degrees C. For the CH4/N-2 (50/50 vol%) mixed gas, the Ni-MOF-74/SBS-15 sample exhibited increasing CH4 permeability (74.7 vs 36.7 Barrer), while selectivity remained unchanged relative to that of the pure SBS membrane.