The　mechanism　on　biomass　reduction　of　low-grade　manganese　dioxide　ore　was　studied　by　investigating　influence　factors　on　manganese　recovery　degree,　such　as　the　reaction　temperature,　time,　biomass/ore　ratio,　compositions　of　biomass,　nitrogen　flow　rate,　and　particle　size　of　raw　materials,　and　it　was　further　identified　through　analysis　of　gas　composition　in　the　outlet　gas,　X-ray　powder　diffraction　(XRD),　scanning　electron　microscopy　(SEM),　and　energy-dispersive　X-ray　spectroscopy　(EDS)　for　the　reduced　sample.　The　results　show　that　the　reduction　process　involved　mainly　two　steps:　(1)　The　biomass　was　first　pyrolyzed　to　release　reductive　volatiles　and　(2)　manganese　oxide　ore　was　reacted　with　the　reductive　volatiles.　By　an　analysis　of　gas　composition　in　the　outlet　gas,　it　was　also　found　that　the　ratio　of　biomass/ore　had　an　important　effect　on　the　reduction　mechanism.　With　a　low　biomass/ore　ratio　of　0.5:10,　the　reducing　reaction　of　the　reductive　volatiles　with　manganese　dioxide　ore　proceeded　mainly　in　two　stages:　(1)　The　condensable　volatiles　(tar)　released　from　biomass　pyrolysis　reacted　with　manganese　oxide　ore　to　produce　reductive　noncondensable　gases　such　as　hydrogen,　carbon　monoxide,　and　some　light　hydrocarbons;　and　(2)　the　small　molecule　gases　further　participated　in　the　reduction.　XRD　pattern　analysis　on　the　reduced　manganese　dioxide　ore　revealed　that　the　process　of　biomass　reduction　of　manganese　ore　underwent　in　phases　(MnO2　-＞　Mn3O4　-＞　MnO).　The　kinetics　study　showed　the　reduction　process　was　controlled　by　a　gas-solid　reaction　between　biomass　volatiles　and　manganese　oxide　ore　with　activation　energy　E　of　53.64　kJ　mol(-1)　and　frequency　factor　A　of　5.45　x　10(3)　minutes(-1).