Hydrogels　are　considered　indispensable　materials　for　fabricating　flexible　devices　with　their　excellent　flexibility　and　workability.　To　efficiently　transform　hydrogels　into　flexible　devices,　three-dimensional　printing　technology　offers　a　powerful　approach.　However,　hydrogels　suitable　for　a　single　printing　strategy　have　proven　inadequate　for　fabricating　flexible　integrated　devices.　Herein,　we　report　a　simple　and　two-phase　3D-printed　hydrogel　(TP-3DPgel)　achieved　through　a　controlled　microphase-separation　strategy.　The　microphase-separation　regions　can　undergo　reversible　changes　through　pH　adjustment,　giving　TP-3DPgel　an　extremely　broad　viscosity　tuning　range　from　liquid　to　solid　states.　This　overcomes　limitations　imposed　by　extreme　rheological　properties　in　different　3D　printing　processes,　making　this　ink　suitable　for　both　liquid-phase　digital　light　processing　(DLP)　3D　printing　and　solid-phase　direct　ink　writing　(DIW)　3D　printing.　Simultaneously,　the　TP-3DPgel　exhibits　excellent　mechanical　properties,　including　high　stretchability　(＞1100%),　high　strength　(0.82　MPa),　low　hysteresis　(∼5.4%),　and　fatigue　resistance.　Moreover,　TP-3DPgel　exhibits　high-resolution　3D　printing　capabilities,　making　it　suitable　for　both　DLP　and　DIW-3D　printing　to　achieve　high-quality　fabrication　from　2D　filaments　to　3D　structures.　Interestingly,　we　utilized　both　DIW　and　DLP-3D　printing　to　fabricate　various　functional　flexible　devices,　including　energy　storage　devices,　sensors,　and　electronic　skins,　showing　in　detail　the　outstanding　compatibility　and　processability　of　TP-3DPgel,　which　offered　a　reliable　strategy　for　3D　printing　functional　devices.　©　2024　American　Chemical　Society.