The invention belongs to the technical field of coalmine production and construction, and particularly relates to a rock cross-cut coal uncovering section coal body dust reduction and reinforcement structure and a construction method thereof. The rock cross-cut coal uncovering section coal body dust reduction and reinforcement structure comprises a reinforcement layer arranged on the surface of a coal body and a plurality of water injection holes penetrating the interior of the coal body; the reinforcement layer is formed by cement spraying; the water injection holes are radially distributed in the direction from the surface of the coal body to the interior of the coal body; in the water injection stage, a dilatation water injector is arranged in each water injection hole; after completion of water injection, the water injection holes are filled with concrete, and steel wire ropes are pre-buried in the concrete. According to the rock cross-cut coal uncovering section coal body dust reduction and reinforcement structure and the construction method thereof, the water injection holes are radially distributed, in the water injection stage, as the sealing depth is great, greater water injection pressure can be applied, water can fully diffuse to moisture the coal body so as to achieve the dust reduction effect; besides, in the reinforcement stage, concrete columns in the water injection holes can wrap the coal body, so that the reinforcement effect is greatly improved.