Abstract: In magnetic finishing, the slotted shape of the polished surface of the permanent magnet is one of the key factors affecting the finishing quality. In this paper, the slot angle span of 30°is used, and the NdFeB material with the grade of N35 is used as the main body of the permanent magnet. Combining a variety of geometric shapes to simulate the relationship between the simulated magnetic field strength and the angle angle of the retained geometric surface, the magnetic field is obtained. The intensity value increases with the decrease of the angle of the geometric surface remaining after slotting, and the maximum value is obtained at the sharp corners, and the higher the magnetic field intensity value, the smaller the corresponding area. Based on this conclusion, a 75° trapezoidal slotted permanent magnet pole is designed with a theoretical magnetic field strength of 1.2~1.4 T. After comparing the current 90° rectangular slotted magnetic poles with the same parameters for the surface magnetic test and grinding S31603 stainless steel plate test, the results show that the 75° trapezoidal slotted magnetic pole table has a relative increase in magnetic strength of 0.2~0.3 T, reaching 1.298 1 T, and a relatively high grinding efficiency. About 20%.