The work aims to improve the grinding quality and efficiency of the inner surface of pipe by magnetic abrasive finishing by exploring the influence of different shapes of aggregate magnetic iron plates on the inner surface of the pipe. Firstly, maxwell software was used to simulate magnetic field intensity and magnetic induction line for axial grooved and non-grooved aggregate magnetic iron plates and analyze the magnetic induction intensity variation and magnetic field intensity distribution of different shapes of aggregate magnetic iron plates. Secondly, the inner surface of the workpiece was polished by magnetic abrasive finishing. Finally, the surface roughness of the workpiece after grinding was measured, and the microscopic morphology was observed. When the speed of magnetic abrasive finishing tool was 500 r/min and the processing time was 15 min, the aggregate magnetic iron plate was not slotted and surface roughness decreased from 0.509 μm to 0.127 μm, with a roughness improvement rate (%ΔRa) of 75.04%. When the aggregate magnetic iron plate was axially slotted, the surface roughness of the workpiece was reduced from 0.553 μm to 0.097 μm, with a roughness improvement rate (%ΔRa) of 82.45%. Under the same processing conditions, when the aggregate magnetic iron plate is axially slotted, the inner surface of the pipe is better polished than that by the non-grooved aggregate magnetic iron plate in the axial direction and the surface roughness improvement rate and the grinding efficiency are better.