Abstract: In order to prepare an effective adsorbent to remediate arsenic pollution, ferrihydrite@biochar composite materials (Fh@BC) were synthesized using ferrihydrite (Fh) and peanut shell biochar (BC) as raw materials. The property of the composite material for adsorption of arsenic was explored. Then, the adsorbent was characterized by SEM-EDS, BET, XRD, FTIR and XPS. Additionally, the simplified sequential leaching was used to analyze the speciation of adsorbed arsenic and evaluate the stability of arsenic adsorption process. The results show that the ferrihydrite was successfully loaded on biochar, the total pore volume and specific surface area of the composite material was effectively improved compared to pure ferrihydrite. Furthermore, the adsorption of arsenic by the composite material was better described by the Langmuir model and the pseudo-second-order kinetic model, and the maximum arsenic adsorption capacity of the composite material could reach to 80.09 mg·g^-1. Moreover, the composite material could adsorb arsenic in a wide pH range. The ferrihydrite particles on the surface of the composite material played an important role in the adsorption of arsenic. The mechanism of arsenic removal mainly includes electrostatic attraction and coordination complexation. In addition, the stable arsenic of the arsenic adsorbed by the composite material accounted for 99.18% of the total amount, and the risk of secondary release of pollutants was low.