In this study, the electronic structure and optical properties of graphene oxide in different structures with single point defect are studied under local density of states approximation and generalized gradient approximation by first-principles calculations based on the density functional theory. The results show that four models are mechanically stable, among which the oxide graphene containing unsaturated oxygen atoms shows an important application potential in water cracking and catalysis. The calculated band structures and partial-wave density of states show that the model containing unsaturated oxygen atoms exhibits indirect band gap, while other models exhibit direct band gap, and the doping type and band gap values vary with different models. The absorption spectrum of graphene oxide is anisotropic, and the absorption edge moves to the near-UV and visible region in the direction perpendicular to the plane. The optical absorption coefficient containing sp ³ hybrid is slightly higher than that containing sp ² hybrid, suggesting that the carbon-oxygen double bond and hanging bond have important influence on the absorption spectrum.