40CrNiMoA alloy is widely used in key components of energy equipment, but it is prone to wear, corrosion, and other forms of degradation in dusty and humid environments. To solve this issue, this study employed laser cladding technology, incorporating La2O3 into a WC-reinforced Fe-based composite coating to enhance the surface performance of the alloy. By adjusting the La2O3 content, the impact of La2O3 on the coating’s phase composition, microstructure, microhardness, and wear and corrosion resistance was investigated. The findings indicated that adding a suitable amount of La2O3 increased the wetting angle of the single-pass coating and reduced pore number by improving coating fluidity. The coating primarily consisted of α-Fe, γ-Fe, MxCy, and La2O3 addition contributed to grain refinement. When the La2O3 content was 1 wt.%, the coating exhibited a maximum average hardness of 544.25 HV0.2, representing a 20.43% increase in relation to that achieved by the coating without La2O3. Furthermore, its wear resistance was significantly improved, with the specific wear rate loss reduced by 32.6 %, with the wear mechanism dominated by mild adhesive and abrasive wear. Notably, La2O3-induced grain refinement effectively hindered Cl− penetration, thereby endowing the composite coating with excellent corrosion resistance.