Abstract: In order to optimize the magnetic system design of magnetic separation equipment more ef⁃ fectively and improve the utilization efficiency of magnetic field，taking the three-pole open magnetic sys⁃ tem as the object，the magnetic system formed by multi-layer Nd-Fe-B blocks was simulated by gradually increasing the number of Nd-Fe-B magnetic blocks.The magnetic field distribution characteristics and the variation of magnetic induction intensity of the magnetic system under different magnetic pole distances are further explored.Through simulation research，it is concluded that the magnetic induction intensity is propor⁃ tional to the number of Nd-Fe-B blocks，and inversely proportional to the utilization efficiency and depth of action of magnetic materials. The increase of the magnetic pole distance will slow down the trend of the mag⁃ netic induction intensity decreasing with the increase of the action depth.When the action depth is 50 mm， the magnetic induction intensity of the magnetic system with large magnetic pole distance reverses the mag⁃ netic induction intensity of the magnetic system with small magnetic pole distance.Therefore，there is an op⁃ timal combination value between the number of different magnetic blocks and the magnetic pole distance at different depths of action，which can maximize the performance of the magnetic material.

Key words: magnetic separator, magnetic system, Nd-Fe-B block, magnetic field strength, magnet? ic pole distance, simulation analysis