In　recent　years,　solid　waste　iron　sludge　(red　mud,　iron-containing　water　treatment　residues,　and　iron-rich　sludge)　has　been　widely　used　to　remove　pollutants　in　the　water　environment;　however,　the　difficulty　of　separating　powdered　iron　sludge　from　the　water　environment　media　makes　it　impossible　to　apply　it　as　a　water　treatment　material　on　a　large　scale,　and　preparing　iron　sludge　into　magnetic　materials　that　are　easy　to　be　separated　is　one　of　the　effective　strategies　to　solve　this　bottleneck.　According　to　the　existing　research　on　iron　sludge-based　magnetic　materials　at　home　and　abroad,　the　preparation　methods　of　magnetic　materials　using　iron　sludge　as　raw　materials　are　summarized,　including　a　series　of　methods,　including　the　thermal　decomposition　method,　hydrothermal　and　solvothermal　method,　co-precipitation　method,　reduction　roasting　method,　and　carbonization　method.　Additionally,　it　is　pointed　out　that　the　currently　commonly　used　preparation　methods　are　thermal　decomposition,　hydrothermal　and　solvothermal,　and　co-precipitation.　In　addition,　the　performance　and　application　of　these　magnetic　materials　as　adsorbents　or　catalysts　in　water　treatment　are　also　summarized.　In　general,　iron　sludge-based　magnetic　materials　can　better　absorb　heavy　metals　and　organic　pollutants　in　water.　The　main　adsorption　mechanisms　are　complexation,　electrostatic　interaction,　reduction,　cation　exchange,　and　precipitation.　As　a　catalyst,　it　can　efficiently　oxidize　and　degrade　organic　pollutants　by　generating　strong　oxidizing　substances:　SO4-•and　•OH.　Although　there　have　been　many　studies　on　the　preparation　and　application　of　iron　sludge-based　magnetic　materials,　because　the　raw　material　iron　sludge　contains　many　impurities,　the　magnetic　materials　prepared　from　iron　sludge　also　have　certain　impurities.　Therefore,　it　is　still　necessary　to　strengthen　the　research　on　the　safety　of　iron　sludge-based　magnetic　materials　in　the　future　to　further　ensure　that　they　can　be　used　as　environmentally　friendly　materials　for　water　environment　restoration.　©　2022,　Science　Press.　All　right　reserved.