Avidin was immobilized on chemically oxidized silicon substrate by means of the surface self-assembling method，and consecutive tethered lipid bilayer membrane was formed after vesicle fusion on such modified substrate.The structures of this tethered membrane were investigated by atomic force microscopy（AFM）.Due to the introduction of a 5 nm water cushion layer between the lipid bilayer and the substrate，a ripple phase was observed in this tethered membrane.The structure of such tethered membrane was different from the simple supported bilayer.These experimental observations demonstrated that the thickness increase of water-layer could effectively reduce the interaction between lipid bilayer and substrate.