Abstract: To investigate the influence of Nb element on the microstructure and properties of the Fe-Cr-Ni coating, Fe-Cr-Ni-Nb coatings with Nb mass fractions of 0%, 0.05%, 0.1%, and 1.2% were prepared by laser cladding. The results show that with the increase of Nb content, the length of columnar crystals in the coating microstructure decreases; the number of cellular crystals increases, and the eutectic structure changes from spherical and fine rod-like to lamellar, strip-like, and network structures. The addition of Nb promotes the precipitation of Laves phase and NbC phase, and the precipitated phases mainly gather in the eutectic zone and form compounds with Cr. When Nb is not added, the eutectic structure is composed of Cr₂B and FeNi solid solution; when the Nb mass fraction is 0.05% and 0.1%, Nb exists in the form of solid solution; when the Nb mass fraction is 1.2%, the Nb element is enriched, and Cr₂Nb precipitates along the grain boundaries. Mechanical property test results indicate that with the increase of Nb content, the hardness of the coating increases significantly, and the hardness of the 1.2% Nb coating is 30% higher than that of the coating without Nb. Tensile test results show that with the increase of Nb content, the tensile strength and elongation after fracture first increase and then decrease. The 0.1% Nb coating exhibits the optimal tensile properties, with a tensile strength of 750.2 MPa and an elongation after fracture of 19.22%. Fracture analysis indicates that the coating exhibits quasi-cleavage fracture when Nb is not added; with the increase of Nb content, the dimple size increases, and the toughness improves; in the 1.2% Nb coating, cracks propagate along the Laves phase; the fracture mode transforms into ductile-brittle mixed fracture, and the toughness decreases.