The utility model relates to an underwater Christmas tree hydraulic internal clamping type lifting tool. The lifting tool comprises an outer barrel, an inner barrel, a cover plate, a supporting plate, an opening locking ring, a pushing block, a spring and a hydraulic cylinder. The inner barrel and the pushing block are both provided with stepped shaft shoulders, and the spring is mounted between the inner barrel and the pushing block. The cover plate and the supporting plate are connected to the upper side and the lower side of the inner barrel through bolts. The outer barrel and the hydraulic cylinder are connected with the cover plate through bolts. The pushing block is arranged between the outer barrel and the inner barrel and is rigidly connected with a piston rod of the hydraulic cylinder. The opening locking ring is arranged outside the inner barrel in a sleeving mode. The pushing block moves up and down under the action of the hydraulic cylinder and the spring, so that the opening locking ring is strutted open, and a Christmas tree is locked. The opening locking ring is rigidly retracted by itself, and the Christmas tree is unlocked. By means of the underwater Christmas tree hydraulic internal clamping type lifting tool, the Christmas tree can be lifted and transported, the structure is simple, the assembling and disassembling procedure is simple and convenient, and unnecessary friction between the lifting tool and the Christmas tree can be reduced.