The invention relates to the technical field of ship sheet machining auxiliary structures, and discloses a jacking cross beam mounting structure of a ship sheet. The structure comprises a segmented carrying trolley, hydraulic devices, a mounting frame and a jacking cross beam; the hydraulic devices are arranged on the two sides of the segmented carrying trolley, the mounting frame is arranged on the tops of the two hydraulic devices, grooves are formed in the tops, and the bottom of the jacking cross beam is arranged in the grooves. According to the jacking cross beam mounting structure of theship sheet, the bottom of the jacking cross beam is placed in the grooves, a limiting shaft is used for limiting the jacking cross beam, through control over a push structure, wedge plates mutually act with a third wedge block, a first wedge block and a second wedge block, the wedge plates on the two sides of the jacking cross beam are controlled to clamp the jacking cross beam for fixing, detaching and fixing of a screw are not needed, the replacing efficiency of the jacking cross beam is improved, and the ship sheet machining and transporting efficiency is improved.