The invention relates to a rear compound filtering dust mask, which can be connected with self-help breathing apparatus externally. The filtering dust-binding box is installed on pillow, a small breathing mask is equipped in the mouth and nose part, the two of which are connected together through air-breathing pipe and breathing pipe; filtering dust-binding box is equipped with universal interface for self-help breathing apparatus externally, and a plurality of baffle board inside to form labyrinth, the internal wall and baffle is coated with dust-binding cold cream to bind dust. The mask is characterized by large breathing space, large filtering area, circular rotating air flow, small air-breathing resisting force, easy to clean and health care effect.