Electropolish/grinding means for an inner surface of a long tube

The present invention is an electropolishing/grinding device for an inner surface of a long tube, including at least one long tube, one electrode, at least two partitions, one fixed magnet mechanism, one driving apparatus and an axial driven mechanism. The fixed magnet mechanism and the driving apparatus form a magnetic levitation effect, which uses magnetic repulsiveness and magnetic attraction to keep the partitions away from the inner surface and avoid an eccentric situation. One of the two partitions has a plurality of springs, a plurality of protruding objects and a plurality of abrasive devices interconnected and firmly touching the inner surface of the tube for grinding.