Abstract An Al-Ni-Mm-Fe amorphous and nanocrystalline composite coating was prepared onto the surface of AZ91 magnesium alloy by high velocity arc spraying process. And the microstructure of the coating was analyzed by scanning electron microscope (TEM) and X-ray diffraction (XRD). The analysis results indicated that the coating consists of amorphous, nanocrystalline and crystalline phases. It has a dense structure with a low porosity of about 2.0%. Its average micro Vickers hardness value is about 330 HV 0.1 , which is five times than that of AZ91 magnesium alloy (62 HV 0.1 ) and four times than that of pure Al coating (71 HV 0.1 ). The abrasion tests showed that the Al-Ni-Mm-Fe coating exhibits a good abrasion resistance.