Abstract: For the purpose of exploring the effect of parameters on particle moving, the force of particles in a spiral separator was simplified based on infinitesimal method and the characteristic of spiral concentrator.The mathematical model including the particle features and the parameters of spirals was proposed to analyze the effect of parameters on particle moving.Separation experiments were conducted by using different densities materials with the size between 1.0 mm to 0.5 mm in the experimental spiral concentrator and the results were used to verify the accuracy of the model.Effect of parameters on particle moving was analyzed based on the model.The results showed that the radial distance of balanced particles decreases with the increase of the density of particles.Equilibrium radius decreases with the decrease of pitch, flow rate and internal diameter.However, equilibrium radius decreases with the increase of the depth of trough.It is beneficial to coarse coal slim separation using spiral concentrator with lower internal diameter, higher depth of the trough and smaller pitch.