The invention provides a dual sealing device for feeding of a ball mill, which is applied in the technical field of large-scale ball mills. The sealing device comprises an inlet pipe, an auxiliary mounting beam, connecting bolts, a compressing snap ring, compressing angle sealing rubber, an adjusting bolt, a mounting flange, an inner wear resistant rubber slab, an outer wear resistant rubber slab, a compressing plate, a compressing plate bolt, a mounting flange bolt and a feeding bushing. The invention is characterized in that: the dual sealing device for feeding of a ball mill is formed by assembling the auxiliary mounting beam, the mounting flange, the inner wear resistant rubber slab, the compressing plate, the outer wear resistant rubber slab and the compressing angle sealing rubber; during installation, the mounting flange is fixed on the inlet pipe through the auxiliary mounting beam, the compressing angle sealing rubber is fixed on a feeding pipe through the compressing snap ring, one side of the compressing angle sealing rubber parallelly contacts with the inner wear resistant rubber slab, and the other side of the compressing angle sealing rubber contacts with a slope of the outer wear resistant rubber slab. According to the invention, the movable compressing angle sealing rubber, the twofold contacted inner and outer wear resistant rubber slabs and the detachable auxiliary mounting beam are utilized in the dual sealing device; therefore, the advantages of convenient installation, simple adjusting and improvement of work environment for sealing members are obtained.