Despite　the　great　progress　has　been　made　on　device　parameters　and　working　mechanism　of　perovskite-based　memristors,　thermal　instability　under　extreme　conditions　limits　their　performance,　and　thermal　effect　on　their　resistive　switching　(RS)　characteristics　remains　unclear.　Herein,　from　the　viewpoint　of　organic/inorganic　interfacial　interaction　in　a　novel　2D　<100>-oriented　perovskite　[(TZ-H)2(PbBr4)]n　(TZ　=　1H-1,2,4-triazole),　thermal　effect　on　the　RS　performance　of　perovskite-based　memristor　is　investigated.　This　FTO/[(TZ-H)2(PbBr4)]n/Ag　memristor　can　exhibit　high　thermal　tolerance　with　a　working　temperature　of　170 °C,　and　the　best　RS　characteristics　can　be　achieved　at　140 °C.　Mechanistic　studies　are　executed　based　on　X-ray　single　structural　analysis,　powder　X-ray　diffraction,　UV–Vis,　and　fluorescence.　Before　the　occurrence　of　phase　change　below　140 °C　(α-phase),　anisotropic　lattice　expansion　illustrated　by　the　weaker　inter-layer　N-H···Br　hydrogen　bond,　longer　layer–layer　distances,　more　distorted　PbBr6　octrahedra,　larger　optical　gap,　and　quenched　fluorescence　can　be　beneficial　for　the　trap-filled　limited　process.　After　phase　transformation　into　β-phase,　the　breakage　of　layer–layer　interaction　and　looser　layer–layer　packing　will　inhibit　the　halogen　migration,　resulting　in　more　space　charge　limited　conduction　characters.　The　unique　thermal　enhanced　RS　performance　with　status　monitored　by　fluorescent　chromism　can　provide　a　new　paradigm　for　the　development　of　new　memristors　with　highly　environmental　tolerance.　©　2022　Wiley-VCH　GmbH.