The invention provides a fastening device and a deep drilling ground stress wireless testing device, and relates to the field of deep rock engineering ground stress testing. The fastening device is applied to the deep drilling ground stress wireless testing device. The deep drilling ground stress wireless testing device comprises a hole bottom instrument. The fastening device comprises a shell, anelastic member and a resisting member. A first accommodation cavity is formed in the shell, and the first accommodation cavity is used for accommodating the elastic member and the resisting member. The shell is used for being detachably connected with the hole bottom instrument, and the resisting member is movably disposed in the shell. The shell is provided with a first resisting portion in an inwardly protruding mode, one end of the elastic member abuts against the first resisting portion, and the other end of the elastic member abuts against the resisting member. The resisting member is used for moving relative to the shell under the abutting and holding action of the hole bottom instrument when the hole bottom instrument is connected with the shell so as to compress the elastic member. The fastening device can tightly clamp the hole bottom instrument to prevent unnecessary loss due to that the hole bottom instrument falls off during the deep drilling process.