Abstract: In order to improve density regulation ability of traditional three- product dense medium cyclone in the second phase,an adjustable magnetic field,a Maxwell finite element analysis software and a new designed separation process were added. The numerical simulation results showed that,the magnetic force in the middle of cyclone was zero,with the increase of radius,the magnetic force rose which increased to the maximum near the inner wall. The magnetic field intensity could be adjusted by current intensity. As the current rose,the underflow density and theoretical separation density increased from 1. 454 g / cm3 to 1. 604 g / cm3 and from 1. 440 g / cm3 to 1. 566 g / cm3 respectively. The overflow density decreased from 1. 162 g / cm3 to 1. 126 g / cm3. The results showed that the current intensity changed the density field and moved the separation cone to the direction of cyclone wall. The experimental results agreed well with the numerical simulation results.