The disclosure relates to the field of underground salt cavern energy storage, and discloses a coupling numerical simulation method for site selection of an underground salt cavern hydrogen storage, which specifically comprises the following. Geological data of an area where the salt cavern hydrogen storage is to be established is obtained. A three-dimensional model is established and grid meshing is performed. An initial coupling field is established and balanced based on the geological model, and then excavation simulation of the salt cavern hydrogen storage is performed. A geological model after excavation and related parameter values thereof are imported into TOUGH2MP software, a stress model in FLAC3D software is coupled with hydraulic and thermal models in the TOUGH2MP software to simulate a stress, hydraulic, and thermal coupling behavior process of rock layers around the salt cavern hydrogen storage in the area, and a coupled simulation result is obtained.