Here we present a combined DFT and molecular dynamics study of uranyl(U(VI)) interaction mechanisms with the calcite(104) surface in aqueous solution. The roles of three anion ligands(CO_3~(2-), HCO_3~-,OH~-) and solvation effect in U(VI) interaction with calcite have been evaluated. According to our calculations, water adsorbed on the calcite(1 0 4) surface prefers to exist in molecular state rather than dissociative state. Energy analysis indicate that the positively charged uranyl species prefers to form surface complexes on the surface, while neutral uranyl species may bind with the surface via both surface complexing and ion exchange reactions of U(Ⅵ)→Ca(Ⅱ). In contrast, the negatively charged uranyl species prefer to interact with the surface via ion exchange reactions of U(Ⅵ) →Ca(Ⅱ), and the one with UO_2(CO_3)_2(H_2O)~(2-)as the reactant becomes the most favorable one in energy. We also found that uranyl adsorption increases the hydrophilic ability of the(104) surface to different extents, where the UO_2(CO_3)_3Ca_2 species contributes to the largest degree of energy changes(-53 kcal/mol). Our calculations proved that the(104) surface also has the ability to immobilize U(Ⅵ) via either surface complexing or ion exchange mechanisms under different pH values. Here we present a combined DFT and molecular dynamics study of uranyl (U (VI)) interaction mechanisms with the calcite (104) surface in aqueous solution. The roles of three anion ligands (CO 3 2-, HCO 3-, According to our calculations, water adsorbed on the calcite (1 0 4) surface prefers to exist in molecular state rather than dissociative state. Energy analysis indicate that the positively charged uranyl species prefers to form surface complexes on the surface, while neutral uranyl species may bind with the surface via both complexed and ion exchange reactions of U (Ⅵ) → Ca (II). In contrast, the negatively charged uranyl species prefer to interact with the surface via ion exchange reactions of U (Ⅵ) → Ca (Ⅱ), and the one with UO_2 (CO_3) _2 (H_2O) ~ (2-) as the reactant becomes the most favorable one in energy. found that uranyl adsorption increases the hydrophilic ability of the (104) surfa ce to different extents, where the UO_2 (CO_3) _3Ca_2 species contributes to the largest degree of energy changes (-53 kcal / mol). Our calculations proved that the (104) surface also has the ability to immobilize U (Ⅵ) via either surface complexing or ion exchange mechanisms under different pH values.