This paper describes an experimental investigation of the effects of the particle blend ratio on surface quality in surface polishing using magnetic polishing liquid (MPL). MPL is produced by mixing sub-micrometer- or micrometer-size abrasive particles into a Magnetic Compound Fluid (MCF), a functional fluid composed of MF(Magnetic Fluid) and MRF (Magneto-rheological Fluid), that reacts with magnetic fields. As a step toward establishing the new surface finishing technology using MPL, it is essential to clarify the effects of the blend ratio of particles to solvent in MPL. For this purpose, first five kinds of kerosene-based MPLs with different blend ratios of particles were prepared, then polishing operations involving stainless steel workpieces were carried out on an experimental rig developed in-house. During the experiments, steady state magnetic fields with different strengths were applied while the contact force between the workpiece and the polishing pad was kept constant. The experimental results showed that the blend ratio of particles affects the work-surface quality significantly. Following SEM and optical microscopy observations of the polished work-surfaces, an appropriate blend ratio, under which the surface roughness improved from the original value of Ra100nm to a final one of Ra24nm after polishing for 30min, was recommended.