Abstract: Coal samples were collected from Huolinhe Coal mine in Inner Mongolia,China,and three kinds of particle size colloids (0-2,2-5,and 5-10 μm) were extracted. The batch experiments have been carried out to study the ad-sorption isotherm and thermodynamics of mercury on colloid from coal. The results show that the sorption was affected by temperature and particle size. When temperature rose,the sorption capacities of colloids from coal were increased. Sorption capacity was decreased as the increase of particle size. The data of sorption isotherm of mercury on colloid from coal was discussed using two kinds of the Dual Adsorption-Partition models. The experimental data fitted the Dual Adsorption-Partition model. For the colloids with sizes “35 ℃ ” >“25 ℃ ”. The value of Gibbs free energy was negative,which showed that the reaction process was spontaneous. Sorption enthalpy was in a range from 24. 5-86. 1 kJ / mol,which indicated that the sorption process was endothermic. The change of entropy value was all positive,which showed that the sorption reaction was an increased randomness process. The adsorption of mercury on the colloid (0-2 μm) was mainly a chemical adsorption process, while on the colloids (2-5 μm and 5-10 μm) were mainly a physical adsorption process.