Abstract Without using any surfactant or template, novel CuS three-dimensional (3D) structures consisting of nanosheets were successfully synthesized via a convenient one-step hydrothermal approach. X-ray diffraction pattern showed that the as-prepared product was pure hexagonal phase CuS. Scanning electron microscopy and high-resolution transmission electron microscopy images revealed that the as-prepared product comprised 3D microspheres (about 1–3 μm in diameter), which were further constructed with randomly oriented, single-crystalline CuS nanosheets (about 20 nm in thickness). The UV–vis absorption spectrum of the as-synthesized CuS 3D microspheres displayed an optical absorption minimum near 672 nm. Besides, the thermal stability of the as-synthesized CuS 3D microspheres was also studied.