Abstract: Utilizing in-situ hot rolling-assisted arc additive manufacturing technology, this study conducted additive remanufacturing of motor shafts with low-alloy steel wire. Through comparative analysis of single-layer and double-layer samples, the study aimed to elucidate the effects of in-situ hot rolling and thermal cycling on the microstructure and mechanical properties of low-alloy steel. The results demonstrated that the microstructure without rolling was predominantly lath martensite. After undergoing rolling, the lath martensite became fragmented and refined, and could further transform into tempered martensite under the influence of thermal cycling. The austenitic grains in the double-layer rolled samples were primarily equiaxed and exhibited characteristics of discontinuous dynamic recrystallization. Compared to the single-layer rolled samples, the average grain size of the original austenite in the double-layer rolled samples was significantly reduced from 95.1 μm to 32.8 μm. Furthermore, in the dilution zone of the cladding layer of the double-layer rolled samples, a notable decrease in microhardness was observed. When comparing the rolled samples to the unrolled samples, the tensile strength increased from 734 MPa to 856 MPa, with a slight reduction in elongation.