The invention relates to a dustproof tire inflation device of a mining engineering vehicle and belongs to the technical field of inflation devices. The device comprises an air pump, an air outlet joint is arranged in the position of an air outlet of the air pump, an air outlet channel is formed in the air outlet joint, multiple flexible valve flaps are sequentially connected to the inner wall of the air outlet joint in the circumferential direction, and the flexible valve flaps freely extend in the direction of the central axis of the air outlet joint to the same center point. By the adoptionof the dustproof tire inflation device of the mining engineering vehicle, the flexible valve flaps are arranged in the air outlet joint and freely extend in the direction of the central axis of the air outlet joint to the same center point, when inflation operation is not conducted, the air outlet channel is sealed through the flexible valve flaps, mineral powder is prevented from entering the airpump, and the air pump is protected; and when inflation is conducted, under the effect of the airflow of the air pump, the flexible valve flaps are blown open, the air outlet channel is opened, and inflation is achieved smoothly.