In the field of using polymeric membranes for gas separation, increasing membrane efficiency (simultaneous increase of permeability and selectivity) is one of the important issues in research related to membrane science and technology. One of the practical and important ways to improve the performance of these membranes is incorporation of different fillers into the polymer membrane matrix. Due to the magnitude of extracting helium from natural gas, the separation of helium from methane and nitrogen using mixed matrix membranes is discussed here. For this purpose, two metal organic frameworks, Cu-BTC and Cu-BDC, were prepared with different morphologies as well as particle sizes and combined with Matrimid polymer. Various tests such as XRD, BET, SEM, TEM, AFM, TGA, DSC and density measurements were used to evaluate the structure of membranes as well as the prepared MOFs. By adding fillers to the polymer matrix, the glass transition temperature of the membranes increased, which is due to the stiffness of the polymeric chains as a result of proper interactions between the particles and the polymer. Also, a decrease in fractional free volume and an increase in thermal stability of membranes were observed by adding fillers. By adding Cu-BTC and Cu-BDC bulk fillers to the Matrimid matrix, helium permeability values as well as selectivity were improved and the best performance in a membrane with 30% of Cu-BDC particles, having helium permeability 61.8 Barrer and selectivity He/CH 4 equals 257.9 and He/N 2 equals 193.4, which was a large increase compared to the values of pure Matrimid and approached the Robson line. To ameliorate the performance of Cu-BTC particles, the size of these fillers was reduced to less than one micron, and the membrane results showed a significant increase of up to 40% loading, so that the selectivity of He/CH 4 and He/N 2 developed by 181% and 169%, respectively. The combination of Cu-BDC sheet fillers with Matrimid intensified the molecular sieve properties at low loads, unlike bulk particles, and greatly increased selectivity. For example, at 15% loading, the selectivities of He/CH 4 and He/N 2 were 410 and 341.7, respectively, which increased by 212 and 246% compared to Matrimid. In membranes containing sheet particles, helium permeability gradually decreased due to the accumulation of sheets, causing the final performance of the membrane to be below the Robson line. To solve this problem in the last part, mixed matrix membranes with Cu-BDC sheet particles and 6FDA-DAM permeable polymer were prepared and the results obtained at 15% loading showed the best performance among all the prepared membranes. In this loading, the selectivity of He/CH 4 and He/N 2 was 309.8 and 244.8, respectively, which improved by 2570 and 2319 % compared to pure 6FDA-DAM membrane, and the membrane performance with helium permeability was 464.7 Barrer crossed the Robson Line 2008. Keywords: Mixed Matrix Membranes (MMMs), Helium Separation, Metal Organic Frameworks (MOFs), Effect of Particles Morphology, Matrimid.