The composite mixed matrix membranes (MMMs) were prepared by incorporating mesopore SBA-15 as a filler to discuss the effects of its particle shape, particle size, and loadings on the organic inorganic interfacial morphology. The SBA-15 was synthesized by template method and it's particle shape and size was adjusted by adding electrolyte. The results indicated that the spherical SBA-15 can improve the dispersion and have better adhesion with organic phase, which showed better permselectivity than the rod-like one. The SBA-15 filler also could increase the diffusion selectivity of MMMs by the addition of different particle sizes. The permeabilities of H-2 and CO2 were 1207.9 and 552.86 Barrer, respectively, with selectivities of H-2/CH4 and CO2/CH4 reached 247.0 and 112.8, respectively, when 1.6 gm spherical SBA-15 was added at 3 wt. %. The dissimilarity occurring in the perm selectivity values with changes made in the particle shape and size are much more pronounced at the lower SBA-15 loading, which exceeded the 2008 Robeson's upper bound limited. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.