The surface wettability of micron particles affects many engineering applications, such as forth flotation and dust removing. The settling velocities of glass beads with diameters in the range 15-100 mu m and varying surface wettability were obtained using a high-speed dynamic system. The results showed that the surface wettability of the particle surface has a significant effect on the terminal settling velocity (V-T) when the particle dimensionless diameter (d* = (Delta g/v(2))(1/3)d) is less than two. As the contact angles increase, the V-T increases and the drag coefficient (C-D) decreases. The classical Stokes model does not reflect this change: consequently, a modified Stokes model that considers surface wettability is proposed. Experimental results indicate that the average relative error of the proposed model is 3.10% for the modified settling velocity formula, and 3.06% for modified drag coefficient formula. Both modified formulas were validated using the experimental data of spherical aluminum oxide (Al2O3) particles. (C) 2020 Elsevier B.V. All rights reserved.