The utility model relates to a near-net-shape beam blank continuous casting machine tundish water gap centering device. The near-net-shape beam blank continuous casting machine tundish water gap centering device is characterized by comprising a centering rod (1), a fixing sleeve (2), a supporting block (3) and a base seat (4). The fixing sleeve (2) is fixed on the base seat (4). The centering rod (1) is arranged inside the fixing sleeve (2) in a sleeved mode. The centering rod (1) can move inside the fixing sleeve (2) along the axial direction of the fixing sleeve (2). The supporting block (3) is arranged on the edge portion of the base seat (4). The near-net shape beam blank continuous casting machine tundish water gap centering device solves the problem of bleed-out caused by the centering badness of tundish and a water gap. The bleed-out accidents are reduced by over 80 %. A fissure of a beam blank web is obviously reduced. The fissure quantity of the web is reduced by 30-40 %, and therefore the production organization is stabilized and the steel production is improved.