The invention relates to an anti-loose retreat stopping nut, and belongs to the technical field of fasteners. A check washer can contract inwards in the radial direction, threaded inner teeth are driven to be pressed into the tooth bottom of a bolt outer thread, and locking relative to a bolt is achieved. The check washer generates and keeps radial pre-tightening force relative to the bolt, influences from impacts, vibration or the load changing action are avoided, and loose preventing and retreat stopping are reliable. When axial pre-tightening force is reduced and disappears, the locking state of the check washer cannot be influenced, disengaging from a connected piece can be avoided, and accidents are prevented. During mounting and dismounting, the outer thread of the bolt can be deformed, the deformed bolt outer thread can be reshaped, a thread pair is not damaged, multi-time repeated usage can be achieved, and the connecting strength and rigidity are not reduced. A limiting washerand the check washer can share the axial load of a main nut, reliability is high, and the service life is long. A lock washer and the check washer are in butt joint through a radial convex mark and aradial concave mark, relative rotation can be avoided, and the mounting and dismounting operation is easy.