Electrides　in　a　two-dimensional　(2D)　scale,　especially　those　that　capture　inherent　magnetism　and　have　low　work　functions,　have　shown　great　application　prospects　in　nanoscale　spintronic　devices　and　electronic　emitters.　However,　searching　for　ideal　2D　magnetic　electrides　is　still　a　great　challenge.　Herein,　based　on　first-principles　calculations,　we　demonstrate　that　2D　CaCl　is　strippable　from　the　heterostructure　of　experimental　CaCl/graphene　and　reveal　that　the　freestanding　2D　CaCl　has　a　novel　electride　phase.　In　this　material,　sufficient　electrons　are　trapped　in　the　lattice　voids　and　act　as　anions　within　the　positive　crystalline　framework,　following　the　electride　form　of　[CaCl](+)center　dot　e(-).　Due　to　the　unique　electron　behaviour　of　electrides,　the　2D　[CaCl](+)center　dot　e(-)　possesses　a　series　of　interesting　physical　phenomena:　(1)　the　electride　[CaCl](+)center　dot　e(-)　exhibits　room-temperature　ferromagnetism,　where　the　magnetic　moment　originates　from　the　excess　electrons　with　an　s-like　orbital　feature　rather　than　the　atomic　orbital　ones,　which　is　drastically　different　from　traditional　2D　ferromagnets;　(2)　the　electride　[CaCl](+)center　dot　e(-)　shows　magnetic　metal　characteristics,　and　by　doping　with　halogen　elements,　its　electronic　structure　can　be　effectively　regulated;　(3)　most　remarkably,　the　FM　electride　[CaCl](+)center　dot　e(-)　shows　an　extremely　low　work　function　(2.65　eV).　This　value　is　the　lowest　among　the　electrides　in　2D　materials　reported　so　far.　Besides,　the　dimension　of　excess　electrons　can　be　effectively　regulated　by　controlling　the　temperature.　This　work　provides　an　excellent　candidate　to　investigate　2D　magnetic　electrides　and　their　associated　applications.