In this work, we have developed a facile and rapid synthesis of urchin-shaped Fe₃O₄@Bi₂S₃ core-shell hierarchical structures through a sonochemical method. The as-prepared Fe₃O₄@Bi₂S₃ hierarchical core-shell structures show excellent photocatalytic efficiency for the degradation of rhodamine B (RhB) and retained this photocatalytic activity after being recycled five times with the help of an external magnetic field. The possible mechanism for the formation of the urchin-shaped Fe₃O₄@Bi₂S₃ core-shell structures is also proposed. These novel urchin-shaped Fe₃O₄@Bi₂S₃ core-shell structures may have potential applications in water treatment, sensors, and energy storage.