PurposeThis　paper　aims　to　propose　a　system　dynamics　model　of　blockchain　online　community　knowledge　sharing,　with　the　following　goals:　to　reveal　the　internal　mechanism　of　blockchain　technology　on　community　knowledge　sharing;　to　show　the　impact　of　blockchain　technology　on　knowledge　sharing;　and　to　promote　knowledge　sharing　and　the　self-development　of　blockchain　online　communities.Design/methodology/approachBased　on　the　core　characteristic　factors　of　blockchain　technology,　including　incentive　mechanism,　trust　mechanism,　information　protection　mechanism,　etc.,　a　knowledge　sharing　analysis　framework　is　established.　Through　the　use　of　the　Vensim　PLE　(Personal　Learning　Version)　software,　according　to　the　steps　of　＂putting　forward　a　dynamic　hypothesis＂,　＂establishing　a　system　dynamic　equations＂,　and　then　＂model　testing＂　and　＂simulation＂,　the　article　analyzes　in　depth　the　process　and　extent　of　the　impact　of　the　above　features　on　online　community　knowledge　sharing.FindingsThe　results　show　that　the　blockchain　incentive　mechanism,　trust　mechanism　and　information　protection　mechanism　all　contribute　to　promoting　an　increase　in　the　number　of　community　knowledge　sharing　users,　as　well　as　in　the　total　amount　of　knowledge　shared.　The　results　also　show　that　the　token　reward　in　the　incentive　mechanism　has　in　fact　a　higher　degree　of　influence　than　the　trust　and　information　protection　mechanisms.Originality/valueAt　present,　no　research　on　the　internal　mechanism　of　knowledge　sharing　in　blockchain　online　communities　has　been　carried　out.　This　article　plays　a　complementary　role　in　research　in　this　field,　and　offers　significant　guidance　for　promoting　online　community　knowledge　management　and　online　community　development.