Abstract: In the present study, a Fe-based cored wire was used to deposit coatings containing Fe-based amorphous phase and fine crystallites on a mild steel substrate by arc spraying.The microstructure and properties of coatings were investigated by XRD, SEM, TEM and micro-hardness meter;and the grain size of the coatings was determined from the corresponding peak via the Scherrer formula.The experiment results show that the coating has homogenous laminated microstructure and contains only a little micro-pores and oxides, Fe-based amorphous phase and nanocrystalline grains are observed in the coating, and the grain size of the crystalline is between 10-40 nm.The volume content of the amorphous phase in the coating amounts to 55.3% by the X-ray diffraction intensity curve.The coating is hard, with microhardness value about 1 260 HV0.1.