In　situ　liquid　phase　transmission　electron　microscopy　(TEM)　and　three-dimensional　electron　tomography　are　powerful　tools　for　investigating　the　growth　mechanism　of　MOFs　and　understanding　the　factors　that　influence　their　particle　morphology.　However,　their　combined　application　to　the　study　of　MOF　etching　dynamics　is　limited　due　to　the　challenges　of　the　technique　such　as　sample　preparation,　limited　field　of　view,　low　electron　density,　and　data　analysis　complexity.　In　this　research,　we　present　a　study　employing　in　situ　liquid　phase　TEM　to　investigate　the　etching　mechanism　of　colloidal　zeolitic　imidazolate　framework　(ZIF)　nanoparticles.　The　etching　process　involves　two　distinct　stages,　resulting　in　the　development　of　porous　structures　as　well　as　partially　and　fully　hollow　morphologies.　The　etching　process　is　induced　by　exposure　to　an　acid　solution,　and　both　in　situ　and　ex　situ　experiments　demonstrate　that　the　outer　layer　etches　faster　leading　to　overall　volume　shrinking　(stage　I)　while　the　inner　layer　etches　faster　giving　a　hollow　morphology　(stage　II),　although　both　the　outer　layer　and　inner　layer　have　been　etched　in　the　whole　process.　3D　electron　tomography　was　used　to　quantify　the　properties　of　the　hollow　structures　which　show　that　the　ZIF-67　crystal　etching　rate　is　larger　than　that　of　the　ZIF-8　crystal　at　the　same　pH　value.　This　study　provides　valuable　insights　into　MOF　particle　morphology　control　and　can　lead　to　the　development　of　novel　MOF-based　materials　with　tailored　properties　for　various　applications.