The invention discloses an ocean travelling crane. The ocean travelling crane comprises a crane winch, which is provided with a plurality of layers of steel wire ropes in a coiled manner; a rotating guiding roller, which is used to guide the steel wire ropes coiled to the crane winch or unreeled steel wire ropes, and rotates at predetermined angles along with the changing of the layers of the steel wire ropes coiled on the crane winch. The ocean travelling crane is used to prevent the twisting of the steel wire ropes between the crane winch and the roller or the steel wire ropes from disengaging from the roller, and therefore damages on the steel wire ropes and parts contacted or connected with the steel wire ropes.