Coupled　THM　(thermal-hydromechanical)　processes　have　become　increasingly　important　in　studying　the　issues　affecting　subsurface　flow　systems.　CO2　permeability　of　the　fracture　in　caprock　is　a　key　factor　that　affects　sealing　efficiency　of　caprock.　A　new　model　associated　with　coupled　THM　processes　that　shows　a　good　reliability　was　derived.　Then,　based　on　the　COMSOL　multiphysics　software,　a　series　of　numerical　calculations　were　performed　on　caprock　models　with　a　single　fracture　subject　to　coupled　THM　effects.　Transmissivity　of　the　fracture　as　a　function　of　fracture　angle,　overburden　pressure,　fluid　pressure　difference,　injected　CO2　temperature,　and　the　initial　fracture　aperture　was　elucidated,　respectively.　Average　transmissivity　of　the　fracture　undergoes　an　increase　by　1.74　times　with　the　fracture　angle　(45　degrees-90　degrees),　2-3　orders　of　magnitude　with　the　fluid　pressure　difference　(5-30MPa),　and　4-5　orders　of　magnitude　with　the　initial　fracture　aperture　(0.05-0.5　mm),　while　it　decreases　by　3-4　orders　of　magnitude　as　overburden　pressure　increases　from　30　to　80MPa.　Injected　CO2　temperature　has　a　small　impact　on　the　fracture　permeability.　This　work　provides　an　alternative　tool　to　enrich　the　numerical　modeling　for　the　assessment　of　CO2　caprock　sealing　efficiency.