In　order　to　effectively　solve　the　problem　of　strength　and　ductility　mismatch　of　magnesium　(Mg)　matrix　composites,　carbon　nanotubes　(CNTs)　are　added　as　reinforcement.　However,　it　is　difficult　to　uniformly　disperse　CNTs　in　a　metal　matrix　to　form　composites.　In　this　paper,　electrophoretic　deposition　(EPD)　was　used　to　obtain　layered　units,　and　then　the　CNTs/Mg　layered　units　were　sintered　by　spark　plasma　sintering　to　synthesize　layered　CNTs/Mg　composites.　The　deposition　morphology　of　the　layered　units　obtained　by　EPD　and　the　microstructure,　damping　properties,　and　mechanical　properties　of　the　composite　material　were　analyzed.　The　results　show　that　the　strength　and　ductility　of　the　composite　sample　sintered　at　590　°C　were　improved　compared　with　the　layered　pure　Mg　and　the　composite　sample　sintered　at　600　°C.　Compared　with　pure　Mg,　the　composites　rolled　by　40%　had　a　much　higher　strength　but　no　significant　decrease　in　ductility.　The　damping　properties　of　the　CNTs/Mg　composites　were　tested.　The　damping–test-temperature　curve　(tanδ~T)　rose　gradually　with　increasing　temperature　in　the　range　of　room　temperature　to　350　°C,　and　two　internal　friction　peaks　appeared.　The　damping　properties　of　the　tested　composites　at　room　temperature　decreased　with　increasing　frequency.　The　layered　structure　of　the　CNTs/Mg　had　ultra-high　strengthening　efficiency　and　maintained　its　ductility.　The　layered　units　prepared　by　EPD　can　uniformly　disperse　the　CNTs　in　the　composites.　©　2022　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.