The work aims to improve the surface quality and surface roughness improvement rate of the inner surface of the thick-wall tube processed by magnetic abrasive finishing, the magnetic induction intensity change and magnetic field line distribution of cooperation between the different number of tile poles and clustered disk were simulated and analyzed by the method of combining clustered disk and tile type magnetic poles with simulation software. The inner surface of the pipe fittings was tested and verified by the magnetic abrasive finishing method. After grinding, the surface roughness of the workpiece was measured, and the microscopic morphology of the workpiece surface was observed. The influence of the number of shoe-shaped magnetic poles, the spindle speed and the particle size of magnetic abrasive finishing on the surface quality of the inner wall of the pipe was analyzed. The results show that under the conditions of no tile magnetic poles were set, spindle speed of 600 r/min, the abrasive particle size of 185 μm and grinding time of 15 min, the original surface roughness of the inner surface of pipe fittings decreased from about 0.42 μm to about 0.14 μm, surface roughness improvement rate was 67.05% and the surface quality was improved; under setting two tile magnetic poles, and the same conditions of, pipe rotation speed, the surface roughness of pipe fittings decreased from 0.42 μm to 0.09 μm, surface roughness improvement rate was 78.57% and the surface defects were completely removed. The magnetic pole distribution with the combination of clustered disk and magnetic tile can form a closed magnetic loop inside and outside the pipe fitting, which magnetic induction intensity of the processing area is improved and the processing efficiency is improved. Surface defects such as micro-cracks and pits on the inner surface of the workpiece are basically removed, and good surface machining quality and higher surface roughness improvement rate is obtained.