The work aims to study microstructure and properties of Fe-based laser cladding with different Ni content. Fe-based laser cladding with different Ni content was prepared with CO2 laser. Phase, microstructure and mechanical properties of the laser cladding layer were characterized with Olympus optical microscope, field emission scanning electron microscope, X-ray diffractometer and Rockwell apparatus. When the Ni content was 10%~11%, phase of cladding layer was mainly composed of α-Fe phase, and also contained a little γ-Fe phase, Rockwell hardness was 35.1HRC, and residual stress of cladding layer was macroscopically presented as tensile stress. When the Ni content was 6%~7%, the cladding layer was mainly composed of α-Fe phase, and also contained a little γ-Fe phase, Rockwell hardness was 47.9HRC, and residual stress of cladding layer was macroscopically close to equilibrium state. When the Ni content was between 2% and 3%, the cladding layer was mainly composed of α-Fe phase, the Rockwell hardness was 60.3HRC, and the residual stress of the cladding layer was macroscopically presented as compressive stress. The cladding layer with different content of Ni is mainly composed of α-Fe phase and γ-Fe phase. With the decrease of Ni content, the diffraction peak intensity corresponding to γ-Fe phase in the cladding layer weakens continuously, the diffraction peak intensity corresponding to α-Fe in the cladding layer increases gradually, grain size decreases, Rockwell hardness increases, residual stress force gradually transforms from tensile stress into compressive stress, effectively inhibiting the generation of cracks, thereby high hardness non-cracking cladding layer can be obtained.