Multifunctional superparamagnetic attapulgite/Fe₃O₄/polyaniline (APT/Fe₃O₄/PANI) nanocomposites have been fabricated by a one-pot process using Fe(III) as the oxidant for aniline and the precursor of Fe₃O₄ in the presence of attapulgite. The introduction of attapulgite can effectively induce the uniform encapsulation of polyaniline and Fe₃O₄ nanoparticles on the surface of attapulgite to form the Anthurium andraeanum-like structure, preventing the formation of free aggregates of polyaniline and Fe₃O₄ nanoparticles. The morphologies and the magnetic properties of the as-prepared nanocomposites can be facilely controlled by adjusting the molar ratio of aniline to Fe(III). The APT/Fe₃O₄/PANI nanocomposites can be used as an adsorbent for the removal of dyes and the enrichment of Au(III) from the solution. In addition, the adsorbed Au(III) could be reduced to elemental gold to obtain APT/Fe₃O₄/PANI supported Au nanocomposites due to the good redox activities of PANI, which exhibited excellent catalytic activity toward the catalytic reduction of 4-nitrophenol in the presence of NaBH₄.