The influence of loads and the intensity of electromagnetic field on tribological performances of lubricating oils doped with different mass fraction of chlorinated paraffin was investigated on a modified fourball tester.The worn surfaces were analyzed by a scanning electron microscope(SEM) and energy spectrum analyzer(EDS),and the possible mechanisms under electromagnetic field were discussed.The results indicate that the wear scar diameters of the worn surfaces lubricated by the tested oils and friction coefficients under electromagnetic field are smaller than those under nonelectromagnetic field,demonstrating the favorable effect of the electromagnetic field on the antiwear and frictionreducing properties of the formulated oils.The improvement of antiwear and frictionreducing properties of the formulated oils is more significant with the increasing of the intensity of electromagnetic field.The concentrations of oxygen and chlorine under electromagnetic field are higher than those under nonelectromagnetic field,indicating that the electromagnetic field is beneficial to the adsorption of ferric chloride film on the surface of the rubbing pairs,and the generation of tribochemical reaction film.