<p>Fe-doped polypyrrole hollow microspheres were prepared by <i>in situ</i> chemical oxidative polymerization. By ultrasonically dispersing the pyrrole monomer on the surface of a hollow ferroferric oxide hard template, the pyrrole monomer was uniformly distributed on the template surface and within the cavity, enabling simultaneous polymerization of pyrrole and Fe doping. The resulting Fe-doped polypyrrole hollow microspheres exhibited a regular spherical morphology with sizes in the micron range and a specific surface area of 116.7 m²/g. The adsorption characteristics of acid chrome blue K (AK) onto the iron-doped polypyrrole were systematically investigated, including the effects of pH, contact time, temperature, and initial dye concentration. The adsorption kinetics showed that equilibrium was reached within 50 min, and the experimental data were well described by the pseudo-second-order kinetic model. Thermodynamic analysis indicated that the adsorption of AK onto Fe-doped polypyrrole hollow microspheres is a spontaneous process. The Fe-doped polypyrrole exhibits advantages such as simple preparation, fast adsorption rate, and recyclability as an adsorbent. It offers an efficient, economical, and environmentally friendly approach, demonstrating strong potential for the treatment of high-concentration printing and dyeing wastewater.</p>