Abstract: The behavior of wear debris and its effect on the tribological properties of 45 steel pin against 302 stainless steel disk under the magnetic field were investigated using the self-developed pin-disk tribometer. For this reason, the distribution characteristics of wear debris on the worn surface of specimen were analyzed with and without the magnetic field. The morphologies of the wear debris and worn surface of 45 steel pin were characterized by means of scanning electron microscopy. The relative height of various areas on the worn surface was characterized by using 3-D surface profiler. Compared with the case without the magnetic field, the wear of 45 steel pin specimen increased, whereas the friction coefficient of the couple was reduced with the magnetic field. In the process of friction, the material of 302 stainless steel disk was transferred onto the worn surface of 45 steel pin and the discontinuous transfer layer was observed. The transfer layer on the worn surface bore the vast majority of friction and wear and tended to be smooth. A small amount of wear debris was adsorbed on the worn surface of 45 steel pin and became fine and oxidized with the magnetic field. To a certain extent the wear debris adsorbed on the worn surface reduced the friction coefficient and hindered the material transfer between the tribo-couple and then increased the wear of 45 steel pin.