Fixing device of round pipe polishing machine

The utility model relates to a round tube polishing machine fixing device which comprises a bottom plate, the top end of the bottom plate is fixedly connected with a limiting sliding rail, the top end of the limiting sliding rail is connected with a sliding base in a sliding mode, the top end of the sliding base is connected with a rotating base in a rotating mode, and one side of the rotating base is fixedly connected with a first fixing frame. Through the arrangement of the rotating shaft, the first fixing frame and the second fixing frame, the limiting sliding blocks on the two sides are driven to slide oppositely by rotating the rotating shaft, the supporting plates are pushed to slide outwards through the connecting plates, the inner wall of a pipe body is supported and fixed, then polishing is conducted, and when the interior of the pipe body needs to be polished, a plug pin is pulled out at the moment; the rotating base is rotated by 90 degrees, the pipe body is placed on the inner side of the outer fi