Abstract: Currently, the complexity and enhanced treatment requirements of arsenic contamination in river water highlight the critical need for efficient filter materials. In this paper, a novel alumina-based iron-manganese composite filter material（RFM-3） is synthesized via hydrothermal method and evaluated for its performance in treating arsenic-contaminated wastewater. Advanced characterization techniques, including scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and Fourier-transform infrared spectroscopy（FT-IR）, are employed to conduct a comprehensive characterization of the filter material’s morphology, crystalline structure, and surface chemistry. Results demonstrate that RFM-3 exhibited a nanostructured particle-supported configuration with a high specific surface area, where surface hydroxyl groups（—OH） play a dominant role in arsenic adsorption. RFM-3 achieves a significant arsenic removal rate of 95.63% at an initial arsenic concentration of 0.5 mg/L and maintained efficient removal across a pH value range of 4-10 and in environments with high ionic strength. Furthermore, the filter material retained its stability with only a 3% decrease in adsorption efficiency after undergoing 10 regeneration cycles, as confirmed by dynamic simulation experiments. In conclusion, RFM-3 is identified as a novel arsenic adsorbent with high efficiency and stability, showing considerable potential for practical applications.