A　coupled　thermal-mechanical　model　of　the　rotary　swaging　of　pure　magnesium　was　developed　using　the　general　finite-element　software　program　MSC/Marc　to　visualize　the　effect　of　axial　feeding　velocity　on　the　rotary　swaging　process.　The　radial　displacement　occurring　in　one　pulse　impact　increases　in　proportion　to　axial　feeding　velocity　(nu(ax)).　When　the　other　processing　parameters　are　fixed,　the　surface　roughness　of　the　swaged　bar　increases　with　nu(ax)　and　is　in　parabolic　relation　with　nu(ax).　There　exists　a　minimum　velocity　nu(ax,　min)　below　which　the　decrease　of　nu(ax)　will　no　longer　improve　the　surface　roughness.　Under　the　technological　conditions　of　this　simulation,　when　the　finial　diameter　d=6.6　mm,　nu(ax,　min)=1.82　m/min,　and　when　d=7.0　mm,　nu(ax　min)=1.83　m/min.　If　R-a=3.2　is　required　for　the　end　product,　then　nu(ax,　min)=6.02　m/min　is　gotten　for　d=6.6　min　and　nu(ax,　min)=7.05　m/min　for　d=7.0mm.　The　increase　of　v.　has　no　notable　influence　on　strain　distribution　along　radial　direction.　The　errors　between　the　experimental　and　simulated　height　of　the　spiral　spine-like　ridges　are　below　8.0%.