A steelmaking converter bottom blowing device is characterized in that a moving supporting ring ear of a converter is made into a ladder shape, one end of which is connected with a supporting ring ear orifice sleeve with a pair-arrange spherical center adjusting bearing arranged in the middle part, while the other end of which is connected with an air-supplying rotation inner sleeve and an outer sleeve and a cooling water rotation inner sleeve and an outer sleeve are connected with the end of the moving supporting ring ear. An aeration slot is arranged inside the air-supplying rotation inner sleeve, which is connected with one end of a transition bend pipe and the other end of the transition bend pipe is communicated with an axial air-supplying deep hole positioned inside the moving supporting ring ear. A water-passing slot is arranged inside the cooling water rotation inner sleeve, which is connected with a backwater pipe and relative rotation can be carried out between the air-supplying rotation inner sleeve and the outer sleeve as well as between the cooling water rotation inner sleeve and the outer sleeve. An air-supplying steel tube which goes through the furnace bottom is arranged on the lower part of the moving supporting ring ear and is communicated with a radial hole inside the moving supporting ring ear. The utility model can separate the air and water and can eliminate the serious potential danger that air and water coexist in the pipe inside the converter supporting ring ear. Besides, the cutting or supplementing furnace shell holes can be carried out without bridging a shelf in the hearth of the converter and the installation and the welding of the air-supplying steel tube can go synchronously with the repairing and the building of the backup lining bricks, which is not only good for safety, but can also save the examining time.