H-2-rich gas has been widely regarded as a promising energy to substitute fossil energy in iron ore sintering process for CO2 reduction. This investigation mainly focused on researching the influences of H-2-rich gas injection parameters over sintering bed on sintering performance, and elucidated the potential function mechanism through both experiment and numerical simulation. Results indicated that increasing injection concentration and prolonging injection time within a proper range improved sinter quality, and the recommended value was 0.60.8 % and 8 min, respectively. Injecting H-2-rich gas at earlier sintering stages achieved greater improvement in sintering quality compared with the ones injecting at later sintering stages, and the recommended injection area was 5-13min. Both experiment and numerical simulation results indicated that injecting H-2-rich improved the thermal patterns of sintering bed, with extended high-temperature areas for increasing the generation of high-strength calcium ferrite. Especially when injecting H-2-rich gas under the recommended parameters, the heat distribution in sintering bed was optimized and the sintering quality of upper sintering layer was obviously improved. Finally, an injection method for guiding the industrial application with its essence to inject H-2-rich at earlier sintering stages was proposed. The research findings provide a promising way for the efficient utilization of clean energy in iron ore sintering plants. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.