The high hardness iron-based coating is prepared by using laser cladding, in which the average hardness is about 775 HV and no cracks are found. The results characterizing the coating microstructure show that the coating consists of uniform and tiny cellular dendrites, martensite distributes in primary dendrites, residual austenite is precipitated in the interdendritic region, and carbides distribute dispersively in the residual austenite substrate. The segregation of molybdenum, chromium, wolfram and niobium exists in the interdendritic region, but carbon distributes uniformly in the cladding layer. Many stacking faults are observed in the residual interdendritic austenite, and matensite separats out in the stacking faults intensive area.