As an emerging micro-pollutant, p-arsanilic acid (p-ASA) exist widely in the environment, and it can form highly toxic arsenate and arsenite during the migration and transformation process, which greatly increases the risk of arsenic pollution in the ecosystem. Additionally, three-dimensional (3D) porous block materials have the advantage of stronger adsorption performance, faster adsorption rate and easy recovery, showing broad application prospects in water pollution control. Hence, the aminozed collagen fibers foam (ACFF) with 3D porous block structure was synthesized. The maximum adsorption capacity of ACFF for p-ASA was 476.19 mg·g−1 due to the rich honeycomb porous structure and the synergistic effect of electrostatic attraction, hydrogen bonding effect and amphiphilicity. Moreover, ACFF is not only easy to recycle, but also has good elastic recovery and regeneration performance. The pore size of ACFF was concentrated in the range of 25–5000 nm, and the porosity was 71.66%. ACFF may be an adsorbent with great potential for the removal of organoarsenic contaminants in water.