The invention relates to the technical field of ships, and discloses a marine ventilator. The marine ventilator comprises a transverse cylinder, a vertical cylinder, a cover plate, silencing pieces and a filtering piece, wherein the vertical cylinder is perpendicular to the transverse cylinder; the cover plate is arranged in a cylinder cavity of the transverse cylinder in a vertically movable mode and arranged above the vertical cylinder; the two silencing pieces are symmetrically arranged at two openings of the transverse cylinder; each silencing piece comprises glass wool and a mesh plate, the mesh plate abuts against the side, close to the cover plate, of the glass wool, the thickness of the glass wool is 50 mm, the thickness of the mesh plate is 0.5 mm, the mesh plate is provided with air holes, the hole diameter of the mesh plate is 6 mm, and a hole distance is 6 mm; and the filtering piece is arranged at the end, away from the cover plate, of the vertical cylinder and comprises an ultraviolet disinfection lamp and melt-blown cloth, and the melt-blown cloth is arranged at the end, away from the cover plate, of the ultraviolet disinfection lamp. According to the marine ventilator, multiple functions of noise reduction, disinfection, dehumidification and the like are achieved by optimizing structure, cost is low, space is saved, and operation is convenient.