Abstract: With the increasingly harsh conditions of coal mining, laser cladding technology with excellent performance was widely used in the remanufacture of hydraulic cylinders. However, there were many kinds of cladding powders in the market, and the differences in chemical composition and preparation process were obvious, leading to obvious fluctuate in the performance of laser cladding layer. Four kinds of commercially available iron-based cladding powders were selected as raw materials, and the iron-based cladding layer was prepared on the outer surface of 27SiMn hydraulic cylinder by laser cladding technology. The composition of cladding powders, microstructure and corrosion resistance of the cladding layer were analyzed.The results show that water atomization and gas atomization are the two main preparation technologies for the commercial cladding powder, and the difference in composition of cladding powder is mainly Mo and Nb; Secondly, the four laser cladding layers are mainly martensite, a small amount of retained austenite and carbide. At the same time, the microstructure of the cladding layer changes obviously in the thickness direction, from the columnar dendrite area above the planar crystal zone to the equiaxed dendrite area above the cladding layer, and the component segregation is also alleviated. The corrosion resistance test shows that the corrosion resistance of the cladding layer is affected by the chemical composition and processing technology:firstly, the corrosion is prone to occur in laser cladding defects; secondly, the corrosion resistance of the cladding layer is improved by the addition of Mo element.