Building　up　selective　mass　transfer　channels　in　polymeric　membranes　is　a　promising　strategy　to　fabricate　effective　separation　membranes.　Herein,　a　thioether-functionalized　hydrazone-linked　covalent　organic　framework,　COF-LZU8,　pre-modified　by　Ag　ion,　was　incorporated　for　constructing　aromatic　selective　channels　within　a　commercial　poly　(ether-block　amide)　(Pebax　2533)　membrane.　The　inside　nanochannels　of　resulting　membrane　were　effectively　confirmed　by　measuring　the　affinity　and　the　selective　free　volume　to　toluene　via　quartz　crystal　microbalance　and　low-field　nuclear　magnetic　resonance.　Owing　to　the　selective　channels,　the　Ag-COF-LZU8/Pebax　membrane　presented　a　considerably　enhanced　performance　for　toluene/n-heptane　separation　comparing　with　pristine　Pebax　membranes.　The　optimized　membrane　could　perform　a　permeation　flux　of　293　g/m(2)h　and　a　separation　factor　of　4.03　for　the　separation　of　50　wt%　toluene/n-heptane　mixture.