The invention provides a core holder for permeability detection. The core holder is provided with a casing, a pressing device, a gas guiding device and a sealing device. A square receiving cavity foraccommodating a core is formed in the casing. The pressing device is arranged on the casing and comprises a first pressing member, a second pressing member and a third pressing member respectively extending in a vertical direction, a longitudinal direction and a transverse direction of the receiving cavity. The first pressing member, the second pressing member and the third pressing member can realize true triaxial stress loading on the core. The gas guiding device is communicated with the receiving cavity and is used for conducting air pressure to the core. A sealing device is arranged between the pressing device and the casing and is used for sealing the receiving cavity. In a test, the first pressing member, the second pressing member and the third pressing member can respectively applynormal stress to the core in the vertical direction, the longitudinal direction and the transverse direction. Through adjustment of stress, the stress conditions of different formations can be simulated. Through change of a core arrangement direction, the permeability values of the core in different directions are measured so that the core is saved.