Dynamic　recrystallization　and　strengthening-toughening　effects　were　investigated　in　the　processed　near-　＜　alpha　＞　Ti-xSi　alloy　by　hot　extrusion.　The　yielding　and　ultimate　tensile　strengths　were　enhanced　by　138.5　MPa　and　118.7　MPa　in　the　hot-extruded　Ti-Si　alloy　compared　with　pure　Ti.　The　double　GSS　effects　(gradient　silicon　solutes　-　gradient　shearing　strain)　led　to　the　bimodal　microstructure　(21.8　mu　m　deformed　strips　and　5.2　mu　m　recrystallized　grains)　and　grain　refinement　by　dragging　the　recrystallization　nucleation　and　grains　growth　during　extrusion.　The　yielding　strength　enhancement　was　resulted　from　multi-factor　Si　solid　solution,　grain　refinement　and　oxygen　solid　solution.　Multi-factor　Si　solid　solution　was　found　to　be　the　dominant　mechanism,　which　was　a　summation　of　size　misfit,　modulus　mismatch,　strain　hardening,　narrow　slip　band　and　texture　strengthening.　Obvious　strain　hardening　and　late　necking　occurrence　would　be　positive　in　obtaining　the　excellent　ultimate　tensile　strength.　Ductility　was　maintained　at　22.9%　from　strain　compatibility　and　cracks　suppression.　This　study　may　provide　a　new　understanding　on　the　relationship　among　the　mechanical　properties,　microstructure　and　processing　of　Ti-xSi　alloy.