<p>Ultra-high strength steels (UHSS) are widely used in aerospace but are prone to defects such as wear and cracks during service life. Laser cladding offers superior control over heat input and cooling rates, minimizing thermal distortion and promoting a strong metallurgical bond. This study employed AerMet100 steel as the cladding material to repair 30CrMnSiNi2A steel, with a focus on elucidating the microstructural evolution and mechanical property enhancement within the repaired sample. The microstructure primarily consisted of tempered martensite, martensite, lower bainite, and minor retained austenite. Meanwhile, obvious hardness gradient was also observed. The average hardness of the cladding layer, the heat affected zone and the substrate was 500.1 HV, 422.7 HV and 365.6 HV, respectively. The hardness of the repair zone was significantly higher than that of the substrate. This was attributed to solid solution strengthening and M2C carbide precipitation facilitated by the high Co and Ni content in AerMet100. Furthermore, the repair zone exhibited a higher dislocation density, which further contributed to the increased hardness. The strength of the repaired sample reached 1484&#xa0;MPa, which was improved compared with the matrix performance, indicating that the use of AerMet100 for laser cladding can effectively restore the mechanical properties of 30CrMnSiNi2A steel. This finding provides an effective repair solution for critical aerospace components, particularly landing gear.</p> Graphical Abstract <p></p>