The invention discloses an underwater vertical fair lead, and belongs to the field of marine machinery. The underwater vertical fair lead comprises a support and a guide wheel assembly. The support comprises a first bracket, a second bracket, a connecting plate and two sealing plates, the first bracket and the second bracket are arranged at intervals, two long edges of the connecting plate are fixedly connected with the bottom of the first bracket and the bottom of the second bracket, one sealing plate is fixedly connected with a short edge of the connecting plate, the bottom of the first bracket and the bottom of the second bracket, the other sealing plate is fixedly connected with another short edge of the connecting plate, the bottom of the first bracket and the bottom of the second bracket, the guide wheel assembly comprises a spindle and a pulley, two ends of the spindle are fixedly connected with the first bracket and the second bracket, the pulley is rotatably nested in the spindle and is positioned between the first bracket and the second bracket, and anticorrosion zinc blocks are arranged on the side, which is far away from the pulley, of each of the first bracket and thesecond bracket. The underwater vertical fair lead has the advantage that the underwater vertical fair lead can adapt to underwater work.