The work aims to design a dual magnetic pole grinding method to solve the problem of uneven pressure and repeated adjustment of the gap in the process of plane magnetic particle grinding. Firstly, the mechanism of dual magnetic pole grinding method and the force of a single abrasive particle in grinding area were analyzed, in order to find the main factors that affected the grinding pressure. Secondly, Ansoft Maxwell software was used to simulate the magnetic field of two grinding methods to analyze the magnetic field gradient change in the grinding areas of the two grinding methods, and contrast the influence of the magnetic induction intensity in area integral method. Finally, the test device was designed. The results of theoretical analysis and finite element analysis were verified by experiments. The changes of surface roughness and micro-structure of the workpiece before and after grinding were compared. The grinding pressure of the abrasive particle in the dual magnetic pole grinding method was provided by the magnetic field force completely, which was proportional to the magnetic induction intensity in the grinding area. The magnetic induction intensity in the grinding area of dual magnetic pole grinding method was about 34.56% higher than the “milling type” grinding method. The SUS304 stainless steel plate was ground for 40 min under the same experimental conditions by two methods. The original textures of the surface of the workpiece were removed basically after grinding by dual magnetic pole grinding method. The surface roughness of the workpiece was reduced from 0.25 μm to 0.16 μm, with the reduction rate of 36%. The reduction rate of surface roughness of dual magnetic pole grinding method was about 80% higher than the “milling type” grinding method. The surface roughness curve of the dual magnetic pole grinding method was smooth, the changes of the height difference of the wave crest and wave trough were uniform, and the surface of the workpiece was smooth and flat. The change of magnetic field gradient in the grinding area is obvious in the dual magnetic pole grinding method. The dual magnetic pole grinding method is beneficial to the renewal of magnetic abrasive particles flow, and the grinding pressure is relatively stable. The surface roughness reduction rate of the workpiece is greatly improved and the surface morphology of the workpiece is smooth after grinding by dual magnetic pole grinding method. It has obvious advantages compared with “milling type” grinding method.