Hydrogen-rich gas-based direct reduction has become a promising low-carbon ironmaking route for decarbonising the steel industry. However, the shortage of high-grade hematite concentrates and the low SiO2 content of such feeds make oxidised hematite pellets susceptible to swelling and fines generation during hydrogen-rich shaft-furnace reduction, thereby threatening stable DRI production. In this context, clarifying the role of SiO2 in reduction behaviour and structural stability is essential for defining a suitable compositional window for shaft-furnace pellets. Therefore, this study systematically investigates the effects of SiO2 content on the reduction kinetics, swelling behaviour, pellet strength, degradation performance, phase evolution, and microstructural development of high grade hematite pellets under hydrogen-rich gas-based reduction conditions.