Nanocellulose(NCC)　was　prepared　through　the　acid　hydrolysis　of　microcellulose(MCC)　and　was　reacted　with　maleic　anhydride　to　obtain　carboxyl-functionized　nanocellulose(MA-NCCs).　The　presence　of　-OH　and　-SO3H　on　the　surface　of　rod-like　MA-NCC　was　confirmed　by　Fourier　transform　infrared　spectrometry(FTIR).　Sulfonated　poly(aryl　ether　ether　ketone　ketone)(Ph-SPEEKK)　was　synthesized　with　bis(4-fluorophenyl-methanone)　and　2-phenylhydroquinone　as　monomer.　MA-NCC/Ph-SPEEKK　nanocomposite　membranes　with　different　MA-NCCs　content　were　prepared,　and　their　properties　were　characterized.　Compared　with　Ph-SPEEKK,　MA-NCC/Ph-SPEEKK　nanocomposite　membrane　showed　better　mechanical　and　thermal　properties　and　higher　proton　conductivity.　The　proton　conductivity　of　the　composite　membrane　with　4%(mass　fraction)　MA-NCCs　under　80　degrees　C　was　0.095　S/cm.　And　its　tensile　strength　reached　30.3　MPa,　which　was　21.2%　higher　than　that　of　Ph-SPEEKK　pure　polymer　membrane.