The　elastic　strain　of　conventional　metals　is　usually　below　similar　to　1%.　As　the　metals＇　sizes　decrease　to　approximate　a　few　nanometers,　their　elastic　strains　can　approach　similar　to　8%,　and　they　usually　exhibit　pseudoelastic　strain　that　can　be　as　large　as　similar　to　35%.　Previous　studies　suggested　that　the　pseudoelastic　behaviors　of　nanocrystals　were　attributed　to　distinctive　mechanisms,　including　the　release　of　stored　elastic　energies,　the　temperature　enhanced　surface　diffusion,　etc.　However,　the　atomistic　mechanisms　remain　elusive.　In　this　study,　through　large　numbers　of　in　situ　atomic-scale　tensile-fracture　experiments,　we　report　liquid-drop-like　pseudoelastic　behaviors　of　face-centered-cubic　fractured　single-crystalline　nanowires　with　diameters　varying　from　0.5　to　2.2　nm.　The　ultralarge　liquid-drop-like　pseudoelastic　strain　ranged　from　31.4%　to　81.0%　after　the　nanowire　fracture　was　observed.　The　in　situ　atomic-scale　investigations　revealed　that　the　atomistic　mechanisms　resulted　from　surface　energy　driven　plastic　deformation　including　surface　diffusion　mixed　with　shear　plastic　deformation　as　well　as　the　release　of　true　elastic　energy.　As　the　nanowires＇　diameters　decrease　below　a　critical　value,　the　surface　pressure　can　approach　the　ideal　strength　of　metals.　This　ultralarge　surface　pressure　drives　atoms　to　diffuse　mixed　with　dislocation　nucleation/propagation,　which　ultimately　leads　to　the　fractured　nanowires　exhibiting　liquid-drop-like　pseudoelastic　phenomena.