Previous　researches　on　high-symmetric　metallic　materials　demonstrate　that　the　introduction　of　twins　can　overcome　the　strength-ductility　trade-off.　However,　it　is　uncertain　if　such　a　pathway　is　valid　for　metals　with　a　low-symmetry　crystal　structure.　Here,　the　low-symmetry　body-centered　tetragonal　Sn　achieved　a　simultaneous　enhancement　in　tensile　ductility　from　6　%　to　14　%　elongation　and　strength　from　36　MPa　to　60　MPa　at　77　K　through　pre-twinning　combined　with　room-temperature　self-recrystallization.　The　in-situ　tensile　experiments　reveal　that　the　pre-existing　and　new　deformation　twins,　as　well　as　dynamic　recrystallization　and　multiple　dislocation　planar　slip　contribute　to　the　enhancement　of　cryogenic　mechanical　properties.