The present invention discloses a method for axial separation by an eccentric inner surface of a permanent magnetic drum, comprising: adsorbing materials to be selected that flow through the inner surface field strength and the gradient area of a rotating eccentric drum (2) by using the energy on the inner surface of a rotating permanent magnetic drum (1), wherein materials with lower specific susceptibility pass through a selected material channel (14) consisted of the eccentric drum (2) and the outer surface of the arched drum of a field strength gradient regulating mechanism (5), and flow out of a low magnetic material outlet (9); materials with higher specific susceptibility are absorbed on the rotating eccentric drum (2), and in an area with higher eccentricity, materials with higher specific susceptibility are stripped off, fall into a high magnetic material groove (7), flow to a high magnetic material outlet (8), and then are collected. There also provides a device for axial separation by an eccentric inner surface of a permanent magnetic drum.