The paper uses the theory of micropolar continuum, in which the asymmetric stress tensor is used to describe the stress state. This theory applies to the case of suspension motion between two parallel planes. An analysis of the obtained results shows that the distribution of the concentration of the solid phase of the suspension depends on the diffusion coefficient. It can be concluded that during suspension, stratification into solid and liquid phases occurs. It is shown that when the suspension moves, there are two effects: accumulation of the solid phase (particle) near the axial plane and a decrease in the concentration of the solid phase near the parallel planes.