The utility model discloses a galvanized steel sheet laser overlap joint welding fixture. The galvanized steel sheet laser overlap welding fixture comprises a work table, a cover plate and separation plates, wherein the work table bears two workpieces to be connected in an overlap joint mode, the cover plate is used for protecting non-working area of the workpieces to be connected in an overlap joint mode, and the separation plates are used for guiding welding vapour. a strip-shaped groove is formed in the middle portion of the work table, and two sides of the strip-shaped groove are provided with clamping devices. The cover plate is arranged on the top of the two workpieces to be connected in an overlap joint mode and the two workpieces are overlapped up and down. A cover plate groove corresponding to the strip-shaped groove is formed in the middle of the cover plate. The separation plates are in fence-shaped shapes and symmetrically arranged between the up and down overlapped layers of the two workpieces to be connected in an overlap joint mode; zinc vapor is helped to escape, and the welding defects are avoided. A heat conduction copper plate is arranged in the strip-shaped groove formed in the work table, sufficient heat conduction is guaranteed, and therefore the welding quality is guaranteed. The work table is also provided with a short adjusting screw and a long adjusting screw which are used for keeping sufficient contact of the workpieces to be contacted in an overlap joint mode, the arranging reliability of the cover plate is guaranteed, and the clamping devices are convenient to fix.