The invention provides a foldable crane to reduce influences of overhead construction of the crane on the traffic below the crane to the maximum degree. According to the crane, a main beam and supporting leg cross beams are made to rotate by a certain angle through rotation supporting devices between the main beam and the supporting leg cross beams, the occupied volume of the parked crane is reduced, and influences on the traffic are relieved as much as possible; and the crane is anchored in different folded states through anchoring and positioning devices.