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At interfaces of metal oxide and water,wet-electron states represent the lowest energy pathway for electron transfer,which maybe the important media for photocatalysis.It is found that the energy of wet-electron state is affected strongly by the surface dipole moment.We explored the properties of wet-electron states at the interface of H2O adsorbed on the surface of the polar-nonploar oxide heterostructures,for example,LAO/STO[001]and STO/LAO/STO[001]film.Using the Density functional theory,we calculated H2O adsorption on three types of heterostructures with different interface: (i) (LaO)+/(TiO2)0 (n-type),(ii)(AlO2)-/(SrO)0 (p-type),(iii) both (LaO)+/(TiO2)0 and (AlO2)-/(SrO)0 (n-p type).For the n-type,the wet-electron state energy increases with the increasing of the LAO thickness.On the contary,for the p-type STO/LAO,wet-electron state energy decreases with the increasing of the LAO thickness.The energy of the wet-electron state could be lower than the Fermi level (Ef) and be occupied when the thickness of LAO reaches 8 layer.For the case of n-p type STO/LAO/STO,the wet electron states of H2O adsorbed on the opposite two STO surfaces show distinctly different properties.On one side they are stabilized below the Ef while on the other side they are pushed to much higher energy.It is known that STO is a good photocatalyst.The occupation of wet-electron states may be helpful in improving the photocatalytic efficiency on STO.