In　this　work,　the　magnetic　chitosan　nanoparticles　were　prepared　by　in-situ　co-precipitation　method　and　then　modified　by　glutaraldehyde　and　ethylenediamine.　The　effect　dose　of　crosslinking　agents　for　adsorbent　preparation　on　tetracycline　(TC)　adsorption　was　investigated.　The　experiment　results　showed　that　the　modified　chitosan　(EMMCS-G)　had　the　best　adsorption　performance,　which　was　more　than　twice　that　of　raw　magnetic　chitosan.　EMMCS-G　was　characterized　by　SEM,　TEM,　VSM,　FTIR,　XRD　and　XPS.　The　effects　of　experimental　parameters　such　as　time,　temperature,　pH,　adsorbent　dosage　and　Cu2+　on　TC　adsorption　by　EMMCS-G　were　discussed.　The　result　indicated　that　the　optimal　pH　was　6.5.　Under　the　conditions　of　an　initial　TC　concentration　of　50　​mg/L　and　an　EMMCS-G　dosage　of　50　​mg,　the　removal　rate　reached　an　impressive　94%.　The　isotherm　and　kinetic　studies　of　adsorption　process　illustrated　that　adsorption　of　TC　onto　EMMCS　corresponded　to　Freundlich　isotherm　and　pseudo-second-order　kinetic　models.　The　maximum　adsorption　capacity　was　84　​mg/g.　Thermodynamic　analysis　revealed　that　adsorption　process　was　both　endothermic　and　spontaneous.　The　regeneration　experiment　suggested　that　the　adsorbent　possessed　excellent　reusability　for　further　use.　Moreover,　the　adsorption　mechanisms　of　TC　onto　EMMCS-G　mainly　involved　pore　filling,　π-π　interactions,　hydrogen　bonding　and　electrostatic　attraction.　©　2023　The　Authors