Abstract: The invention discloses a lock bolt assembly comprising a bolt provided with a first external thread, a mounting nut correspondingly screwed on the bolt and provided with a first internal thread, and a locking piece, wherein in the length direction of the bolt, at least one cantilever part is formed on the mounting nut in an extension mode, and the first internal thread extends onto the cantilever parts; the locking piece is arranged on the mounting nut and can abut against the cantilever parts, so that the areas, where the first internal thread is formed, of the cantilever parts bend and tightly press the first external thread in an abutting mode, then different areas of the first internal thread on the mounting nut abut against and tightly press the first external thread in two opposite directions, and thus the bolt is prevented from rotating relative to the mounting nut.