In present work, the first-principles calculation method based on density functional theory (DFT) was employed to systematically investigate the electronic and optical properties of graphene modified with different oxygen-containing functional groups (epoxy, hydroxyl, carboxyl) and carbon vacancy defects.Six theoretical models were established as follows: graphene modified with epoxy groups on the surface (GO-O), graphene modified with hydroxyl groups on the surface (GO-OH), graphene modified with carboxyl groups on the surface (GO-COOH), epoxy-modified graphene with carbon vacancy defects (GO-O-CD), hydroxyl-modified graphene with carbon vacancy defects (GO-OH-CD), and carboxyl-modified graphene with carbon vacancy defects (GO-COOH-CD). and their geometric structures and structural stability, band structures, density of states (DOS), magnetic properties, as well as dielectric functions, optical absorption spectra and reflection spectra were calculated and analyzed in detail.