Abstract: The invention discloses a anti-loosing, and self locking structural member, which comprises a first threaded section and a second helical elastic deformation section with the same thread pitch, wherein axial sections of threads of the second helical elastic deformation section take the shape of a thin sheet; and the first threaded section has an axial misalign which is not an integral multiple of the pitch relative to the second helical elastic deformation section, such that the threads of the second helical elastic deformation section are helically elastically deformed when screwed into an internal thread, thereby achieving frictional anti-loosing and self-locking and a stable self-locking torsion.