First-principles　calculations　based　on　density　functional　theory　(DFT)　with　the　generalized　gradient　approximation　(GGA-PW91)　have　been　used　to　investigate　the　adsorption　and　dissociation　of　H2O　molecules　on　HfO2(111)　and　(110)　surfaces　at　different　sites　with　different　coverages.　It　was　found　that　the　surface　hafnium　atom　was　the　active　adsorption　position　of　the　(111)　and　(110)　surfaces　when　compared　different　adsorption　energies　and　various　geometrical　parameters.　Adsorption　energies　of　water　on　the　HfO2　(111)　and　(110)　surfaces　varied　slightly　as　the　coverage　increased.　It　was　shown　that　the　most　favorable　configuration　of　H2O　on　the　HfO2(111)　and　(110)　surfaces　corresponded　to　the　coordination　of　H2O　via　its　oxygen　to　a　surface　hafnium　atom.　Adsorption　geometries,　Mulliken　population　charges,　density　of　states,　and　frequency　calculations　for　HfO2-OH,　HfO2-O,　and　HfO2-H　at　both　surfaces　were　also　carried　out.　The　results　showed　that　the　hydroxyl　group　interacted　with　the　surface　by　its　oxygen　atom　to　surface　hafnium　atoms.　Isolated　oxygen　atoms　bound　to　surface　hafnium　and　oxygen　atoms,　while　hydrogen　atoms　interact　only　with　surface　oxygen　atoms　to　form　hydroxyl　groups.　For　the　dissociation　reaction,　according　to　transition　searching,　H2O　-＞　H　(ads)+OH　(ads).　The　energy　barriers　were　endothermic　by　9.7　and　17.3　kJ.mol(-1)　for　the　(111)　surfaces　and　exothermic　by　-59.9　and　-47.6　kJ.mol(-1)　for　the　(110)　surfaces.