Based on density functional theory of first-principle theory, we systematically investigate the electronic structure and optical property of V-, N- monodoping and V-N codopiong and compare with pure ZnO. The results show that the absorption in the visible light region is enhanced for the doped system, especially for V-N codoped ZnO. The calculated biding energy indicates that the V-N codoping is the most stable system, thus, V-N codoped ZnO is considered as an ideal photocatalyst. Moreover, the method of anion-cation codoping could be better used in photoelectrochemistry and also in the preparation of stable and high performance short wavelength photoelectron devices.