The novel polyaniline (PANI)/flower-like CuS composites with improved electromagnetic interference (EMI) shielding effectiveness (SE) were prepared through in situ polymerization of PANI into the flower-like CuS microspheres. X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, UV-vis optical absorption spectroscopy, thermogravimetric analysis, electrical conductivity, and EMI SE were used to characterize the as-obtained products. The results revealed that flower-like CuS was uniformly coated by the PANI shell. Most importantly, compared with original CuS and pure PANI, the novel PANI/flower-like CuS composites exhibited remarkably enhanced shielding effectiveness. With a thickness of 3 mm, the optimal EMI SE of PANI/CuS composites reached -45.2 dB at 2.78 GHz and the improved shielding efficiency below -18 dB was also obtained over the frequency range of 300 kHz-3 GHz, suggesting that these novel PANI/flower-like CuS composites showed a promising application in the field of shielding materials.