Abstract: An Al-based amorphous and nanocrystalline composite coating was prepared by high velocity arc spraying technique.It is found from XRD and TEM analysis results that Al-based amorphous and nanocrystalline composite coating consists of amorphous phases,nanocrystalline phases and crystalline phases.The coating has a obvious layered structure,and layer-to-layer bond is good.It has a compact structure,and no obvious crack and pore.Its porosity is about 1.8%.And the average microhardness of the coating is about 311 HV₁₀₀,which can reach to that of the Al-based amorphous alloys prepared by traditional methods.