In order to study the wear mechanism of AISI 1045 steel during cutting and grinding process and its variation with machining parameters,the tribology behavior of AISI 1045 steels under various sliding velocities and loads were investigated using a CFT-1 multifunction surface comprehension performance tester,and the worn surfaces morphologies were investigated using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS).The results indicate that friction coefficient is decreased significantly and the depth of wear track is increased first then decreased with the increasing of sliding speed.Correspondingly the wear mechanism is transformed from the combination of adhesion wear,abrasive wear and mild oxidation wear to the combination of adhesion wear,abrasive wear and local fatigue wear.With the increasing of load,the friction coefficient has no significant change,the depth of wear track is increased but unchanged between 50 N and 65 N.The wear mechanism is transformed from the combination of mild adhesion wear and abrasive wear to the combination of adhesion wear and abrasive wear and mild oxidation wear.