The invention relates to the technical field of pipeline inner wall polishing, and discloses an inner wall polishing device ignoring the length of a pipeline. The inner wall polishing device solves the problems that different polishing heads need to be replaced when steel pipes with different hole diameters are processed, and the equipment has high cost, a plurality of spare parts of the polishingheads and low productivity; and the inner wall polishing device solves the other problems that inner and outer round polishing equipment only aims at the pipe ends of the steel pipe ends, the equipment is not prone to operating when the inner walls of the longer steel pipes and the shorter steel pipes are cleaned, the length of drive rods needs to be replaced continuously. The inner wall polishing device polishes the inner wall of the pipeline through two sets of polishing heads, threads of a connecting rod which is connected into a second polishing head are arranged as first sliding notches,while the first sliding notches are in tilting state, a connecting rod and a fixing rod which are is connected inside a first polishing head are in an existing inclined state. Therefore, when the second polishing head rotates, the first polishing head rotate in the formed direction of the notches; and the two sets of polishing heads rotate in opposite directions by arranging different thread lines.