Abstract: Seven Shenfu coal powders with different particle sizes were obtained by sieving or ball mill. They were used for adsorption tests to probe the adsorption properties of aniline on different granularity coal powders, especially the ultrafine ones. The results show that the adsorption kinetics of aniline on 4 coal powders with larger particle size fit well Lagergren firstorder model, while the other 3 powders with smaller size follow the secondorder model. The dynamics parameters and the effective diffusion coefficients of aniline adsorption on coal powders were calculated. The adsorption process is governed by inner diffusion of the particles. Aniline adsorption capacity exponentially increases with decreasing mean diameter (d50) of coal powder. The adsorption equilibrium of coal powders (mean diameter d50: 9.30μm, 4.28μm and 4.82μm) can be described in terms of Langmuir isotherm, and the maximum amount to form a complete monolayer on the surface is 109.05×10－3, 246.31×10－3 and 90.91×10－3, respectively. The adsorption capacity of ultrafine coal powders is much better than that of normal coal powder.