The utility model discloses a self -adaptation anti -drop sealing washer relates to sealing washer technical field, in order to solve the problem that sealing washer installation among the prior art is not firm, drop easily, this self -adaptation anti -drop sealing washer cross -section cavity, two rows of one -way cockscomb structure lugs of sealing washer side edge design, it will to work as when the seal groove is packed into to the sealing washer, the cockscomb structure lug is narrowed down by extrusion shrink downwards, after the seal groove of packing into, the sealing washer has under the action of gravity and has the trend that drops downwards, under the effect of frictional force two gang saw cusp lugs of sealing washer side have open trend, can firmly grasp two sides of seal groove, make the sealing washer does not drop in can not following the seal groove, but the cockscomb structure lug has the shrinkage deformation characteristic, the sealing washer has certain self -adaptation scope on width direction.