Magnetic abrasive finishing (MAF) is a kind of method for polishing the surfaces and the edges. The investigation for the technique of MAF and the development of the ferromagnetic poles lay a theoretical foundation for developing a new method for finishing the curved surfaces automatically under the numerical control. In the paper, the performance parameters of the developed magneto poles, which are used for finishing the plane surfaces and the curved ones, have been tested. The curvature of the finished surface, the sloping angle of the machined surface and the rotation speed of the poles, which affect the surface roughness, are studied theoretically. What mentioned above supply references to the practical uses of the MAF, especially in the mould manufacturing.