Since　the　discovery　of　intrinsic　ferromagnetism　in　atomically　thin　Cr(2)Gr(2)Te(6)　and　CrI3　in　2017,　research　on　two-dimensional　(2D)　magnetic　materials　has　become　a　highlighted　topic.　Based　on　2D　magnetic　materials　and　their　heterostructures,　exotic　physical　phenomena　at　the　atomically　thin　limit　have　been　discovered,　such　as　the　quantum　anomalous　Hall　effect,　magneto-electric　multiferroics,　and　magnon　valleytronics.　Furthermore,　magnetism　in　these　ultrathin　magnets　can　be　effectively　controlled　by　external　perturbations,　such　as　electric　field,　strain,　doping,　chemical　functionalization,　and　stacking　engineering.　These　attributes　make　2D　magnets　ideal　platforms　for　fundamental　research　and　promising　candidates　for　various　spintronic　applications.　This　review　aims　at　providing　an　overview　of　the　structures,　properties,　and　external　controls　of　2D　magnets,　as　well　as　the　challenges　and　potential　opportunities　in　this　field.