Crane capable of being integrally lowered

The invention provides a double-beam bridge crane which is unlikely to be limited by the height of a plant. The double-beam bridge crane comprises a trolley, a coiling block and a steel wire, wherein the coiling block is arranged on a left beam end and is connected with a motor; the steel wire is wound with a first plane spiral coil and a second spiral coil on the coiling block on the left beam end, and the winding directions of the first plane spiral coil and the second spiral coil are the same; a first trolley wheel and a second trolley wheel are fixed on one side, on a main beam, of the trolley, and a fixed pulley is fixed on one side, on another main beam, of the trolley; a horizontal fixed pulley is fixed on a right beam end; and after forming the first plane spiral coil, the steel wire sequentially bypasses the first trolley wheel, a first movable pulley, the fixed pulley, a second movable pulley, the second trolley pulley and the horizontal fixed pulley and finally winds the coiling block to form the second plane spiral coil. According to the crane, the original operation mechanisms and hoisting mechanism are not used, so that the trolley is lightened and lowered, then the complete machine is lowered, and thus a trolley frame is relatively light and convenient.