A　single-crystal　Ca24Al28O66　electride　(C12A7:e(-))　with　a　length　of　20　mm　and　a　diameter　of　10　mm　was　prepared　in　one　step　by　the　optical　zone　melting　Al　reduction　method.　The　added　Al　powder　not　only　serves　as　a　composition　component,　but　also　serves　as　anin　situreducing　agent　for　the　preparation　of　single-crystal　C12A7:e(-)　The　results　of　phase　and　structure　analyses　show　that　the　prepared　single-crystal　C12A7:e(-)　has　good　single　crystal　quality.　The　electrical　properties　and　electronic　state　analysis　results　show　that　single-crystal　C12A7:e　exhibits　a　sharp　Raman　absorption　peak　of　electron　injection　at　100-400　cm(--1),　and　an　ultraviolet　absorption　peak　at　2.8　eV.　This　indicates　that　the　preparation　method　achieves　effective　electron　injection　while　forming　a　single-crystal　C12A7　structure.　It　is　calculated　that　the　electron　concentration　of　single-crystal　C12A7:e(-)　with　an　Al　powder　content　of　0.5　reaches　1.2　x　10(18)　cm(-3).　The　results　of　first-principles　calculations　show　that　the　single-crystal　C12A7:e(-)　has　a　cage-cavity　conduction　band　(CCB)　between　-　1　eV　and　0.7　eV,　which　is　beneficial　to　electrical　performance.　The　excellent　electrical　properties　of　single-crystal　C12A7:e(-)　are　mainly　derived　from　the　contribution　of　d-state　electrons　of　the　Ca　atoms.