In　this　study,　the　direct　impregnation　synthesis　strategy　was　employed　to　prepare　a　novel　multi-site　functional　Mn-MOF-74/chitosan　(MMCS)　adsorbent　for　the　effective　adsorption　and　separation　of　tungsten　and　molybdenum.　The　composites　with　high　Mn-MOF-74　loadings　exhibited　high　surface　areas,　network-like　porous　structures,　and　abundant　functional　groups,　which　improved　the　adsorption　performance　of　the　composites.　The　optimal　tungsten　adsorption　capacity　reached　557.6　mg/g,　and　a　tungsten/molybdenum　separation　factor　of　25.25　was　achieved.　The　adsorption　behavior　of　MMCS　can　be　described　by　Langmuir　isotherm　and　pseudosecond-order　kinetic　models,　indicating　single-layer　adsorption.　The　thermodynamic　study　revealed　that　the　surface　adsorption　was　a　spontaneous,　exothermic,　and　entropy-increasing　process.　The　adsorption　mechanism　is　a　synergy　of　electrostatic　effect,　selective　pore　channels,　and　coordination　reaction　(formation　of　W-N　and　Mn-W　coordination　bonds),　based　on　the　result　of　Fourier　transform　infrared　and　X-ray　photoelectron　spectroscopy,　as　well　as　density　functional　theory　calculations.　Due　to　its　strong　affinity　for　HWO4　-,　the　system　preferentially　adsorbs　HWO4　-,　thereby　achieving　efficient　separation　of　tungsten　and　molybdenum.　MMCS　exhibited　excellent　reusability　by　maintaining　a　high　adsorption　capacity　after　five　adsorption-desorption　cycles.　This　study　developed　a　new　type　of　composite　adsorbent　with　good　performance　and　sustainable　characteristics,　providing　an　innovative　solution　for　the　efficient　adsorption　and　separation　of　tungsten　and　molybdenum,　which　is　beneficial　for　the　preparation　of　high-quality　tungsten　or　molybdenum　products　from　complex　resources.