Two novel 3D CuI hierarchical architectures were prepared by a simple hydrothermal method in the presence of poly(vinyl pyrrolidone) (PVP) and triethanolamine (TEA). The observation from scanning electron microscopy showed that both CuI microflowers and microspheres were composed of numerous nanoplates. Interestingly, the morphology of the final products could be controlled by varying the amount of PVP and TEA. A possible formation mechanism was proposed based on the experimental results. When the as prepared CuI microflowers and CuI microspheres were tested as absorbents for Cr(VI) removal, both of them showed excellent adsorption properties. The effect of pH on adsorption, adsorption rate and the Cr(VI) removal capacity was discussed. Results showed that both of the CuI adsorbents exhibited excellent removal capacity and fast adsorption rate for Cr(VI) at a pH value of 3.0. The Cr(VI) removal capacity of CuI microflowers and microspheres could reach to 88.2 mg g⁻¹ and 98.7 mg g⁻¹, respectively.