A large-tonnage component lifting slewing gear matched with a lifting jack in use comprises a connecting support, a slewing driving device, an annular bearing transitional block and a bearing. The connecting support is a cylinder body. Two sides of the cylinder body are respectively provided with a boss inwards or a boss outwards. The slewing driving device comprises a fixed inner ring, a rotary movable ring and a hydraulic motor. The bearing is an annular bearing. When the large-tonnage component lifting slewing gear matched with the lifting jack in use is in a used state, the upper end of the connecting support is connected with the lifting jack and the lower end of the connecting support is fixedly connected with the rotary movable ring of the slewing driving device, so that the lifting jack is connected with the rotary movable ring of the slewing driving device; the annular bearing transitional block is installed on the fixed inner ring of the slewing driving device and the annular bearing transitional block and the fixed inner ring of the slewing driving device are fixed on a bearing platform together through screws, the bearing is installed on the fixed inner ring of the slewing driving device, and the lifting jack is installed above the bearing. The large-tonnage component lifting slewing gear matched with the lifting jack in use can satisfy the installation requirement in a limited space and the construction requirement for large-tonnage component lifting rotation.