The　searching　for　green　memristor　with　good　environmental　robustness　will　be　significant　for　next　gen-eration　biodegradable　devices.　In　this　work,　bio-compatible　and　non-toxic　polydopamine　(PDA)　was　pre-pared　by　self-polymerization　of　dopamine　in　simple　aqueous　solution,　which　was　protonated　by　different　acid　concentrations　(3-12　M　HCl)　and　further　fabricated　as　memory　devices　with　structures　of　FTO/PDA/Ag.　The　ON/OFF　ratio　are　enhanced　gradually　from　2.80　x　102　(PDA-3　M),　8.39　x　102　(PDA-6　M),　5.18　x　103　(PDA-9　M)　to　2.41　x　104　(PDA-12　M).　The　lower　conjugated　degree,　the　closer　lattice　packing　and　the　less　radicals　after　acid　treatment　are　the　reasons　for　the　enhanced　bipolar　resistive　switching　performances　of　proto-nated　PDA-based　memristor.　The　resistive　switching　mechanism　is　the　conductive　filament　with　three　processes　of　Ohm,　space　charge　limited　conduction　(SCLC)　and　trap-filled　limited　(TFL).　In　addition,　the　FTO/　PDA-12　M/Ag　exhibit　good　environmental　robustness,　including　thermal　(100　degrees　C)　and　ionizing　irradiation　(UV　exposure　for　96　h).　In　all,　the　facial　protonation　treatment　and　the　simple　sandwich　device　structures　together　with　good　environmental　robustness　endow　its　promising　applications　in　as　green,　stable　and　biodegradable　next　generation　electron　devices.　(c)　2022　Elsevier　B.V.　All　rights　reserved.