The dense-medium suspension has heterogeneity, which can easily reduce the stability of the suspension under the centrifugal concentration, thereby directly affecting the sorting accuracy of the dense-medium cyclone. In order to reduce the concentration of thesuspension and improve its stability, and according to the paramagnetism characteristic of the dense medium magnetite powder, the radialinward magnetic field force was introduced to adjust the distribution state of the dense medium particles in the cyclone. Herein, the motionlaws of particles in magnetic composite fields were explained using the theoretical calculations, single factor experiment and Box-Behnkenorthogonal experiment design with three factors and three levels. The influence of the feed pressure, the intensity of the excitation currentand the number of coil turns on the distribution of the dense medium and the stability of the suspension was analyzed. The influence of various factors on the concentration efficiency Eth of the suspension was explored; the mathematical model and and its minimum values of response value Eth were provided. The results show that the introduction of radially inward magnetic field force into the centrifugalfield makes the dense medium particles have a lower centrifugal sedimentation velocity and changes the distribution of the dense medium,which increases the density of the overflow and decreases the density of the underflow. With the increase of feed pressure, the concentration C1, clarity C2, stratification C3 and concentration efficiency Eth of the suspension show a similar increasing trend, and a similar decreasing trend with the increase of the excitation current intensity and the number of turns of the coil. In the orthogonal interval, the concentration efficiency Eth is positively linearly correlated with the feed pressure, and negatively linearly correlated with the current intensityand the number of coil turns. The degree of influence is sorted in order of magnitude: feed pressure> coil turns> current intensity. Finally,the linear mathematical model minimum value of Eth is given. When the feed pressure is 0.03 MPa, the current intensity is 3 A, and thenumber of coil turns is 1 000 turns, the concentration efficiency Eth is 0.067. Compared with the concentration efficiency of 0.37 in the absence of a magnetic field, the stability of the suspension is increased by 81.89%.