A　novel　bio-adsorbent　based　on　H3PO4-modified　corn　stalks　(P-CSs)　was　synthesized　and　used　to　adsorb　methylene　blue　(MB)　from　aqueous　solution.　The　successful　modification　of　corn　stalks　by　H3PO4　was　verified　by　using　XPS,　FT-IR,　respectively.　Meanwhile,　the　adsorption　performance　and　the　adsorption　mechanism　of　P-CSs　were　investigated.　This　novel　bio-adsorbent　performed　stably　over　a　considerably　wide　pH　range　of　6.0　similar　to　9.0.　And　electrostatic　attraction　and　ion　exchange　were　involved　in　adsorption　of　MB　on　P-CSs.　Furthermore,　the　adsorption　of　MB　by　P-CSs　perfectly　fitted　the　Langmuir　isotherm　model　(R-2　=　0.997-0.999)　and　pseudo　second　order　kinetic　model　(R-2　=　0.999).　The　q(e)　of　MB　on　P-CSs　was　129　mg/g　at　308　K　by　Langmuir　model,　and　thermodynamic　study　showed　that　MB　adsorption　is　a　spontaneous　exothermic　process.　The　regeneration　and　re-adsorption　experiments　indicated　P-CSs＇s　merit　of　regeneration　with　the　recovery　efficient　of　91%　after　4　adsorption-desorption　cycles.　This　novel　bio-adsorbent　prepared　in　this　work　could　achieve　effective　removal　of　MB　and　could　be　reused　for　4　and　more　adsorption-desorption　cycles　for　MB　removal.