A method was developed to chemically functionalize graphene sheets by silylation. The graphene oxide sheets were silanized with N- (trimethoxysilylpropyl) ethylenediamine triacetic acid. Then the silanized graphene oxide sheets were reduced to produce water-soluble graphene derivatives (EDTA-graphenes). Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy were employed to characterize the structures and properties of the EDTA-graphenes and to monitor changes in the surface morphology and chemical and physical characteristics of graphene at different stages of the silylation reaction. The EDTA-graphenes showed improved dispersion in water and an EDTA-graphene film with a well-layered structure and high conductivity was fabricated.