UiO-66-NH2　nanocrystals　were　synthesized　and　embedded　into　bromomethylated　poly(phenylene　oxide)/polyethersulfone　(BPPO/PES)　polymer　matrix　to　form　UiO-66-NH2/BPPO/PES　mixed　matrix　membranes　(MMMs).　The　crystalline　structure,　interaction　between　UiO-66-NH2　and　BPPO,　and　dispersion　of　UiO-66-NH2　were　characterized　by　FTIR,　XRD,　and　SEM.　Nanoparticle　dispersion　was　drastically　enhanced　with　the　assistance　of　BPPO,　giving　an　improved　adhesion　between　the　polymer　and　filler　particles.　Owing　to　the　intrinsic　adsorption　property　of　UiO-66-NH2　and　BPPO　to　CO2,　the　CO2　permeability　was　significantly　increased.　As　a　result,　the　UiO-66-NH2/BPPO/PES　membrane　exhibited　enhanced　gas　separation　performance,　where　CO2/N-2　and　H-2/N-2　ideal　selectivities　were　increased　to　50.2　and　302.4　with　a　CO2　permeability　of　125.6　Barrer.　(c)　2018　Wiley　Periodicals,　Inc.　J.　Appl.　Polym.　Sci.　2018,　135,　46759.