To　measure　the　parameters　of　fiber　and　to　visualize　the　reshaping　process　of　fiber　in　air　tunnel,　an　experimental　approach　is　developed　in　the　present　work.　The　tunnel　is　designed　with　gradient　flow　velocity,　and　the　fiber　reshaping　images　as　well　as　the　fiber　length　value　are　obtained　experimentally.　An　analytical　expression　of　velocity　distribution　in　the　tunnel　is　theoretically　derived　and　the　simulated　results　are　obtained.　Automatic　fiber　reshaping　including　stretch　and　rotation　is　verified　using　the　dynamical　equation　and　the　multi-spherical　chain　model.　It　is　shown　that　pull　force　by　air　flow　makes　a　chain　of　balls　become　straight　and　Stokes　moment　makes　the　ball　chain　rotate.　Finally,　reshaping　criterion　related　with　flow　velocity　is　formulated.