Abstract: The sorption of Eu(Ⅲ) on Beishan decarbonated soil as a function of pH value, solid-to-liquid ratio, humic acid (HA) and ionic strength was studied using batch technique. The results indicate that Eu(Ⅲ) sorption to soil is strongly dependent on pH and ionic strength, indicating that the outer-sphere complexation and ion exchange may be predominant at low pH; whereas, at high pH range, inner-sphere complexation and/or surface precipitation are prevailing. HA certainly provokes Eu(Ⅲ) sorption to soil under low pH range, but significantly reduces Eu(Ⅲ) sorption at high pH because of the dissolvable-humate complexes in aqueous solution.