Reduced graphene oxide (rGO), as one of graphene-based materials, is prepared by reducing oxygen functional groups on graphene oxide (GO) via either thermal or chemical reduction. Taking advantage of its facile large-scale production through the solution-based processing, rGO has drawn great attention for their potential as an alternative material to pristine graphene. Water usually plays a crucial role on both the chemical preparation of rGO and its various applications. Hence, understanding on water dynamics and states on rGO is crucial for its processing and utilization. Particularly on water vibrational modes revealed by inelastic incoherent neutron scattering, we may recognize the dynamical and structural characteristics of water confined on the surface of rGO.