A series of CuS nanostructures were synthesized by a simple wet chemical method on a large scale in the presence of cetyltrimethylammonium bromide at low temperature. Three typical samples were selected to study the relationship between the morphologies and resulting physical properties. The optical properties of CuS hierarchical structures were investigated by UV/Vis and Raman spectroscopy and the excellent photocatalytic performance was also evaluated by measuring the decomposition rate of methylene blue under natural light. As an absorber, the selected CuS nanostructures possess excellent microwave absorbing properties. When the thickness of the absorber is 3.5 mm, the minimum reflection loss can reach −76.4 dB at 12.64 GHz. The enhanced photocatalytic performance and microwave absorbing properties were also explained based on morphologies of the nanostructures.