The research focuses on investigating the impact of inlet arrangement strategies and particle parameters on the thermochemical performance of Falling Particle Solar Reactors (FPSRs) for methane steam reforming. FPSRs are recognized for their ability to convert solar energy into chemical energy efficiently. The study utilizes the Eulerian-Eulerian model in Fluent 2020 R2 to simulate different particle inlet arrangements, non-uniform mass flow rates, and particle sizes in the reactor. The results indicate that the optimization of inlet arrangement strategies and particle parameters can enhance hydrogen production efficiency. Specifically, the study shows that different arrangement strategies and non-uniform mass flow rates have varying effects on hydrogen production efficiency, with optimal conditions leading to a significant increase in the production rate. Moreover, the research highlights the importance of particle size, demonstrating that smaller particles, such as a 0.15 mm catalyst, exhibit superior hydrogen production efficiency compared to larger sizes. These findings provide valuable insights for improving heat and mass transfer performance in FPSRs and offer guidance for optimizing the design and operation of falling particle solar reactors.