Hierarchical Fe 3 O 4 @Co 3 O 4 core–shell microspheres were prepared through a simple two-step hydrothermal method. The structure, morphology and surface characteristics of the microspheres were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer–Emmett–Teller (BET). The results showed that porous architectures were assembled from Fe 3 O 4 sphere core and Co 3 O 4 flower-like shells. The gas sensing investigations revealed that the Fe 3 O 4 @Co 3 O 4 core–shell microspheres sensors exhibited enhanced sensing properties to acetone compared with Fe 3 O 4 microspheres and Co 3 O 4 nanomaterials, which might be attributed to the unique hierarchical structure and the synergetic effect exerted by Fe 3 O 4 and Co 3 O 4 .