The invention belongs to the technical field of sailing boats, and particularly relates to a folding structure of a sailing boat sail. A foldable sail structure of a full-sea-condition long-voyage unmanned sailboat comprises a base, a vertical frame is installed above one end of the base, the vertical frame is of a hollow structure, a plurality of lifting blocks are installed in the vertical frame, a cross beam rod is installed at one end of each lifting block, and canvas is installed on the cross beam rods; the lifting blocks are connected with the vertical frame in a sliding mode, every two adjacent lifting blocks are connected with each other, and a lifting mechanism used for controlling the lifting blocks to ascend is further installed in the vertical frame.When the structure is used, rising and falling of the canvas can be achieved only by controlling operation of a first motor, the sail of the unmanned sailboat is convenient to unfold and fold, meanwhile, a cloth groove is formed in the inner side of each cross beam rod of the sailing boat, and the canvas penetrates through the cloth grooves, so that it is guaranteed that the canvas can borrow force from the cross beam rods no matter which side of the canvas is blown by wind, the wind resistance strength of the canvas is guaranteed, and the phenomenon that the sailing boat is damaged is avoided.