In order to improve the lubrication and wear reduction ability and electronically controlled friction increasing response characteristics of ionic liquid (IL), Fe3O4 nanoparticles were synthesized by chemical coprecipitation and modified by oleic acid, and dispersed into ionic liquid. On the premise of not exceeding the maximum dissolution limit of ionic liquid, Fe3O4 nanoparticles with mass fractions of 5%, 15% and 30% ionic liquid-based ferromagnetic fluid, and then the friction coefficient changes of pure ionic liquid and ionic liquid based ferromagnetic fluid under normal environment and electric field environment were simulated and tested by using a self-made current carrying friction and wear tester. At the same time, the wear morphology was compared and analyzed by white light interferometer and scanning electron microscope (SEM), The element content and phase composition of the wear area were further analyzed by energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The results showed that the "ball antifriction effect" of Fe3O4 nanoparticles significantly improved the lubrication effect of ionic liquid in normal environment. With the increase of the mass fraction of Fe3O4 nanoparticles, the wear surface gradually became smooth and flat, and the phenomena of peeling and abrasive particle aggregation gradually disappeared, especially when the mass fraction was 30%. There were only shallow furrows and slight scratches in the wear marks of the sample. At this time, the friction coefficient also showed a very low level, about 0.04, which was much lower than 0.085 under pure ionic liquid lubrication, and the wear volume was only 2.12×10?3 mm3 was much lower than 5.41×10?3 mm3 in pure ionic liquid lubrication; At the same time, the "electrodeposition effect" of nanoparticles enhanced the electronically controlled friction increasing response ability of ionic liquid in electric field environment. When the current intensity reached 20 A, the friction coefficient of ionic liquid-based ferromagnetic fluids with mass fraction of 30% was instantaneously increased by nearly one time, and the increase of friction coefficient reached 0.039, which was four times that of pure ionic liquid under the same conditions. Therefore, it could be concluded that the ionic liquid-based ferromagnetic fluid was successfully prepared by dispersing the synthesized and modified Fe3O4 nanoparticles into the ionic liquid, and the lubrication performance and electronically controlled friction increasing response of the ionic liquid were significantly improved by adjusting the content of nanoparticles, In terms of lubrication performance:the spherical Fe3O4 nanoparticles changed the motion mode between friction pairs from relative sliding to relative rolling friction, reduced the severity of friction and improved the lubrication effect. In terms of electronically controlled friction enhancement:due to the electrodeposition effect, the directional movement of nano Fe3O4 particles under the action of electric field made nano Fe3O4 particles easy to deposit and aggregate on the surface of the lower sample, which affected the integrity and fluidity of the lubricating oil film, making the adsorbed oil film of ionic liquid-based ferromagnetic fluid easier to be broken down by current than that of pure ionic liquid, The lack of lubricating adsorption oil film worsened the lubrication conditions, and the micro protrusions between the upper and lower sample surfaces were more likely to make direct contact with each other. At the same time, under the action of current, melting and spot welding were also easy to occur between the friction pair materials. At this time, the friction state was more like severe "dry friction", resulting in a significant increase in the friction coefficient, which was manifested as the phenomenon of electronically controlled friction increase.