[Ca24Al28O64](4+)(4e(-))　has　great　application　prospects　in　electron　emission　and　catalyst　support,　but　suffers　prolonged　synthesis　time　and　complicated　multistep　process.　In　this　work,　a　direct　and　efficient　calciothermic　reaction　was　utilized　for　the　rapid　fabrication　of　subnanoporous　electride　similar　to　[Ca24Al28O64](4+)(4e(-))　directly　from　a　novel　mixture　of　CaAl2O4　(CA),　CaO,　and　Ca　powders　under　milder　conditions　(e.g.,　sintered　at　1070　degrees　C　for　10　min　in　a　vacuum).　Phase-pure　CA　derived　from　calcinating　was　for　the　first　time　used　as　a　precursor　for　the　synthesis　of　dense　C12A7:e(-)　ceramic.　The　as-prepared　C12A7:e(-)　exhibited　an　electron　density　of　similar　to　2.3　x　10(21)　cm(-3),　covering　the　metal-insulator　transition.　The　electron　injection　in　the　as-sintered　C12A7:e(-)　was　verified　by　electron　paramagnetic　resonance　analyses.　Moreover,　thermionic　emission　began　to　occur　at　700　K　and　increased　to　1.8　A/cm(2)　at　1373　K　when　an　extraction　electrical　field　of　3.5　x　10(4)　V/cm　was　applied.　This　demonstration　shines　new　light　on　studies　of　formation　avenues　of　polycrystalline　C12A7:e(-)　structure.