The invention discloses a self-absorption tail door lock. The top of a lock body is provided with a U-shaped groove with an upward opening; an emergency starting arm is arranged in the U-shaped groove; a through hole A is formed in a front top plate of the U-shaped groove and internally provided with a worm gear shaft; a sinking groove is formed in a rear top plate of the lock body; a through hole B is formed in the right portion of the sinking groove; the middle portion of an upper cover plate is a vertical plate with a folded edge; the vertical plate is installed on a step face of the lock body; folded plates A inclined downwards are arranged on the two sides of the front portion of the vertical plate; a flat plate stretching out in the horizontal direction is arranged behind the upper cover plate; the flat plate is installed in the sinking groove of the lock body; a through hole C is formed in the right portion of the flat plate and communicates with the through hole B; a bottom plate is arranged below the upper cover plate; a U-shaped plate is arranged on the middle portion of the bottom plate; and folded plates B downwards inclined are arranged on the two sides of the front portion of the vertical plate of the U-shaped plate. The self-absorption tail door lock is small in structure, achieves the self-absorption function and the pawl releasing function, eliminates the potential safety hazards and has good economic and social benefits during application and popularization.