The critical motion characteristics of mineral particles in an inclined channel were analyzed. A theoretical model based on particle terminal velocity, fluidization superficial velocity, average volume fraction of the incline and the equipment parameters was proposed to describe the critical trajectory of mono-disperse particulate suspensions in an inclined channel. This paper derived a generalized empirical relationship which took inclination angle of the inclined channel and hindered settlement induced by particle-to-particle interaction in the suspension into consideration. The relationship proved to be useful and effective in evaluating the performance of segregation in an inclined channel under the condition that particles exactly passed through the inclined channel. The relationship also proved the throughput advantage of the equipment over a conventional fluidized bed. To verify the model, an experimental system was established. It is found that the model was consistent with the experimental results, which denotes that the main points of this novel critical motion description have been grasped. The research is of certain practical significance to classification of mineral particles, the geometry of the inclined channel as well as operating parameters. (C) 2017 Elsevier B.V. All rights reserved.