Composite materials, having advantages of high specific strength, high specific stiffness, are used in many applications, such as musical instrument, acoustical tile, fire wall, sports equipment, aerospace and vehicle industries. Composite products in the form of sandwich structures are specifically useful in recent years. In this paper, the bending strength of sandwich structure made by graphite/epoxy face laminates and core material made by multi-walled carbon nanotubes (MWNTs) reinforced polymer was investigated experimentally. In experiment, the three-point bending test was performed to measure the bending properties of sandwich beams. The influences of fiber orientation in the face laminates and MWNTs content in polymer reinforced nanocomposite core material on the bending strength of sandwich beams were discussed in this paper. The failure mechanism of sandwich beams with various fiber orientations in the face laminates was also discussed.