Abstract: The aluminum matrix composite reinforced by Al-based amorphous was prepared by friction stir welding.The microstructure of the composite was analyzed by metallography,energy dispersive X-ray spectroscopy(EDS),X-ray diffraction(XRD) and transmission electron microscope(TEM).The test results indicated that the amorphous reinforced materials and metal matrix(5A06 aluminum alloy) were well mixed together by a full stir and an interesting sandwich-mixed structure was formed.A large number of nanoscale structure with 90-400 nm exits in this composites.The nanoscale structure is composed of α-Al and α-Al amorphous structure,which can greatly improve the structure and properties of the composite.Furthermore,the existence of amorphous structure indicated that the amorphous reinforced materials were not completely crystallized during the friction stir processing.