Abstract: The Au(Ⅲ)was adsorbed on polyurethane foam that had been widely used for analysis of micro gold in the geological samples,and the validity of the analytical testing could be improved by the excellent adsorption.The thermodynamics of Au(Ⅲ)adsorption on polyurethane foam was studied by static adsorptionmethod.The results show that the adsorption capacity of Au(Ⅲ)as well as the adsorption volume increases with the initial concentration of Au(Ⅲ) in the range of 2.0-70.0 mg/L,and the increasing temperature was not conducive to the adsorption.The adsorption process was in accordance with Freundlich isotherm adsorption model.Fitting by Van der Hoff equation，ΔHθ was -42.67 kJ/mol and ΔSθ was -130.6 J/(mol·K)in the adsorption.Under the experimental temperature,the adsorption of Au(Ⅲ)on polyurethane foam proceeds spontaneously(ΔGθ<0)and is dominated by physical adsorption.When the temperature rises to a certain degree,the adsorption would become unable to proceed spontaneously.This study will provide thermodynamic data support for the optimum conditions and application of gold enrichment by polyurethane foam in the analysis of gold in the geological samples.