In order to study the influence of H²O on the copper current collector forlithium-ion batteries， adsorption and dissociation of H²O on Cu(111) surface were calculated by thefirst-principles calculation method based on the density functional theory.The related geom-e try， energy barrier， density of states and soon were computed by D mol module of theMaterials Studio package.The results indicated that the most stable adsorption sites of H²Oon a clean and a pre-adsorbed O atom Cu(111) are both topsites， and H²O preferred themolecular adsorption.The analysis on the density of states showed that the orbital hybrid-ization between O ²p andCu₃d states was quite strong for H²O adsorption on pre-adsorbedO surface， and the hybridization was weak on the clean surface.The energy barrier for H²Odissociation on the clean Cu(111) surface was 148.54kJ/mol， while the dissociating energydecreases obviously to 92.73kJ/mol with the aid of the O atom， which revealed that thepre-adsorbed O atom can promote the dissociation of H²O on Cu(111) surface.