The invention provides a large full-
gyration offshore platform crane which relates to the lifting machinery and comprises a rotary column, an arm support, a main lifting
winch, an auxiliary lifting
winch, an arm support variable-breadth
winch, a
gyration bearing drive mechanism, a main hanger hook, an auxiliary hanger hook and a driver cab. The arm support is connected with the middle part of the rotary column through a
hinge point mounted on the root of the arm support; the
lower half part of the rotary column is arranged under a main
deck and connected with a semi-diving platform through the
gyration bearing drive mechanism. The gyration bearing mechanism is composed of an upper radial bearing, a lower radial bearing, a peg-tooth, a three-in-one decelerator, a centripetal
thrust bearing and a rubber support; the upper radial bearing and the lower radial bearing are respectively mounted on the middle and the lower parts of the rotary column. The centripetal
thrust bearing and the
rubber bearing are sequentially mounted on the bottom part of the rotary column; the peg-tooth mounted on the lower
deck is meshed with the three-in-one decelerator mounted on the corresponding position of the rotary column. The large full-gyration offshore platform crane has the advantages of novel, compact and practical structure, high efficiency and being a large full-gyration offshore platform crane with economical and practical properties.