A novel surface finishing method named magnetic shear thickening finishing that combines the intelligent shear thickening fluids and magnetic field action is proposed. The magnetic shear thickening finishing media, which is a combination of carbonyl iron particles and SiC particles in a base medium of shear thickening fluids, is developed. The finishing processes were experimentally characterized to verify the performance potential of the proposed method and developed magnetic shear thickening finishing media. Experimental results demonstrated that the developed media is effective for surface finishing compared with finishing media without shear thickening fluids. The surface roughness value of the testing sample was reduced to 54 nm from an initial value of 1.17 μm. Scanning electron microscope observations showed that the scratches were removed obviously and a smooth surface was obtained.