Abstract <p>As a kind of semiconductor material, zinc oxide has gained wide attention in the field of optoelectronics and catalysis. Four systems of pure modified zinc oxide, modified zinc oxide after Ce doping, modified zinc oxide after Y doping and modified zinc oxide with Ce and Y co-doping were simulated by density functional theory. The adsorption properties and photoelectric properties of different systems were studied separately. The results show that there is competitive adsorption of formaldehyde and water molecules on the surface of modified zinc oxide. After doping, the state density of modified zinc oxide moves to the region with lower energy. The efficiency of adsorption of VOCs on the surface of modified zinc oxide is faster. The conductivity properties of modified zinc oxide are changed and the charge transfer efficiency of modified zinc oxide is improving, which indicating that the modified zinc oxide has catalytic effect.</p>