In recent years, there has been a growing trend in utilizing fibers to improve the crack resistance of asphalt mixtures. However, the examination of steel fiber’s impact on the crack resistance mechanism of hot recycled asphalt mixture remains limited. Steel fibers, characterized by its high strength, toughness, and robust self-healing properties, presents a promising avenue for enhancing the low-temperature performance of hot recycled asphalt mixture. This study investigates the macro- and micro-mechanisms underlying the low-temperature crack resistance of steel fiber-reinforced hot recycled asphalt mixture, to address significant deficiencies in their crack resistance at low temperatures. Five different schemes of steel fiber content (0.1 %, 0.2 %, 0.3 %, 0.4 %, and 0.5 %) were examined, and a three-dimensional numerical model of semi-circular bending (SCB) was constructed utilizing PFC3D (three-dimensional particle flow software). By converting and calibrating macro and micro parameters, meso parameters were defined within the model, yielding SCB simulation results for AC-16 and SMA-16 steel fiber hot recycled asphalt mixture. To evaluate the influence of steel fiber content on the low-temperature crack resistance of the hot recycled asphalt mixtures, fracture energy (Gf), crack resistance index (CRI), and balanced cracking index (BCI) were introduced as evaluation criteria. The simulation outcomes affirm that the disparity between the results of the three-dimensional virtual strength test and those of the indoor strength test remains within 6 %, thus validating the model’s viability. Notably, the failure cracks observed in AC-16 and SMA-16 hot recycled asphalt mixtures predominantly manifest at the interface between the asphalt mortar and recycled asphalt pavement (RAP). After the addition of steel fibers to these mixtures, the fracture energy (Gf) peaks at a steel fiber content of 0.3 %, showing increases of 41.46 % for AC-16 and 32.38 % for SMA-16, respectively. The optimal steel fiber content for both AC-16 and SMA-16 hot recycled asphalt mixtures, as determined by CRI and BCI, was found to be 0.3 %. Beyond the threshold of 0.3 %, the crack resistance diminishes. These findings may enhance the cracking performance of hot recycled asphalt mixture.