CoNiMnP permanent magnetic films have been electroplated into arrayed round dimples (with diameters from 100 μm to 700 μm) machined on the substrate surface (316 stainless steel). These films could be magnetized and could generate the arrayed micro-magnetic field. Compared with normal surfaces (316 stainless steel flat surfaces without any dimples or coatings), the frictional properties of such magnetic surfaces were investigated under different loads and sliding speeds when lubricated with ferrofluids using a friction test rig. Much attention was paid to the effect of the dimple sizes on the lubrication properties. In addition, the magnetic properties of the dimples arrayed surface were analyzed by finite element analysis software (Ansoft Maxwell 3D). The results show that there exists the optimized geometrical parameter of the arrayed magnetic surface, which displays the best tribological performance when lubricated with ferrofluids.