The invention discloses an experimental device for time domain dynamic CT scanning permeability of a low-permeability core. The experimental device comprises a CT scanning permeability core simulation system, a core preprocessing liquid supply system, a core preprocessing vacuum system and a CT scanner, wherein the CT scanning permeability core simulation system comprises a CT scanning core chamber; the CT scanning core chamber comprises a core chamber shell; a columnar core is placed in the core chamber shell; a first end face fixing and a second end face fixing ejector pin are respectively arranged at the two ends of the core chamber shell; a first radial fixing block and a second radial fixing block are respectively arranged on the two sides of the core chamber shell; the core preprocessing liquid supply system comprises an intermediate container; the intermediate container is communicated with the interior of the core chamber shell through a main liquid supply pipeline; the core preprocessing vacuum system comprises a vacuum pump; and the vacuum pump is communicated with the interior of the core chamber shell through a vacuumizing pipeline. The experimental device disclosed by the invention can monitor the permeability change rule of the remaining oil in the micro-pore along with the time under a certain temperature and pressure of a low permeability-ultralow permeability core.