Even　though　modeling　has　been　frequently　used　to　understand　the　autotrophic　deammonification-based　membrane-aerated　biofilm　reactor　(MABR),　the　relationships　between　system-specific　biofilm　property　settings　and　model　predicted　N2O　production　have　yet　to　be　clarified.　To　this　end,　this　study　investigated　the　impacts　of　4　key　biofilm　property　settings　(i.e.,　biofilm　thickness/compactness,　boundary　layer　thickness,　diffusivity　of　soluble　components　in　the　biofilm　structure,　and　biofilm　discretization)　on　one-dimensional　modeling　of　the　MABR,　with　the　focus　on　its　N2O　production.　The　results　showed　that　biofilm　thickness/compactness　(200–1000　μm),　diffusivity　of　soluble　components　in　the　biofilm　structure　(reduction　factor　of　diffusivity:　0.2–0.9),　and　biofilm　discretization　(12–28　grid　points)　significantly　influenced　the　simulated　N2O　production,　while　boundary　layer　thickness　(0–300　μm)　only　played　a　marginal　role.　In　the　studied　ranges　of　biofilm　property　settings,　distinct　upper　and　lower　bounds　of　N2O　production　factor　(i.e.,　the　percentage　ratio　of　N2O　formed　to　NH4+　removed,　5.5%　versus　2.3%)　could　be　predicted.　In　addition　to　the　microbial　community　structure,　the　N2O　production　pathway　contribution　differentiation　was　also　subject　to　changes　in　biofilm　property　settings.　Therefore,　biofilm　properties　need　to　be　quantified　experimentally　or　set　properly　to　model　N2O　production　from　the　MABR　correctly.　As　a　good　practice　for　one-dimensional　modeling　of　N2O　production　from　biofilm-based　reactors,　especially　the　MABR　performing　autotrophic　deammonification,　the　essential　information　about　those　influential　biofilm　property　settings　identified　in　this　study　should　be　disclosed　and　clearly　documented,　thus　ensuring　both　the　reproducibility　of　modeling　results　and　the　reliable　applications　of　N2O　models.　©　2021　Elsevier　Ltd