Crane and arm lifting method thereof

The invention relates to the technical field of cranes, and provides a crane and an arm raising method thereof.The crane comprises a base, a disassembly and assembly supporting leg and a forward lifting supporting leg, the base is provided with a supporting leg connector, the supporting leg connector is detachably connected with the disassembly and assembly supporting leg and the forward lifting supporting leg in a matched mode, and the forward lifting supporting leg is used for forward arm raising of the crane; when the crane starts an arm in the forward direction, the forward lifting supporting leg is connected to the supporting leg connector in the walking direction of the crane and located on the arm lifting side of the crane; and an angle monitoring system is arranged between the front lifting support leg and the side surface of the base, and is used for monitoring the setting angle of the front lifting support leg. The forward lifting supporting legs are arranged, so that the arm lifting stability and t