In order to solve the practical problem of deburring and surface finishing of internal hole surface, mold cavity, complex surface, etc., a new viscoelastic magnetic abrasives is proposed based on analysis of field characteristic and existing finishing process. Viscoelastic magnetic abrasives are prepared, and motion locus of abrasives are discussed. An experimental investigation is engaged on direct hole, keyway surface through a simple test device designed by ourselves. Theoretical analysis and experiments show that all burrs is removed, the edges are rounded off and the surface is smooth, the value of surface roughness Ra drops from 0.53μm to 0.05μm. It’s successful application will effectively solve the practical difficulty of deburring and surface finishing for special shapes such as groove, keyway, etc. and fulfil the quantitative finishing of complex surfaces. It will produce a positive impact on precision surface finishing technology.