The electronic structures and dielectric properties of TiO_(2)-graphene composites are studied using pseudo-potential density functional theory.It is shown that interfacial charge transfer properties of graphene/TiO_(2)are influenced by the atomic type on TiO_(2)surface.The interfacial interaction of graphene with Ti-terminated surface is so strong that it causes a buckling structural graphene,and the titanium atomic d electrons are transferred obviously from TiO_(2)to graphene.It is revealed that dielectric properties of the composites are greatly affected by both band structures and electronic transitions.Compared with bulk TiO_(2),dielectric constants of TiO_(2)-graphene composites are significantly improved.