Cobalt ferrite hollow microspheres with protrusions/polythiophene (CFHMP/PTh) composites were successfully prepared by in-situ polymerization method of thiophene with CFHMP. The morphology, phase structure, thermal stability, static magnetic and electromagnetic parameters of samples were analyzed and characterized by scanning electron microscope (SEM), X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG), vibrating sample magnetometer (VSM) and vector network analyzer (VNA). The results indicate that the saturation magnetization (Ms) and remnant magnetization (Mr) and coercivity (Hc) of CFHMP/PTh composites are 566.4 Oe, 40.8 emu/g and 17.6 emu/g, respectively. The dielectric property of CFHMP/PTh composites is better than that of CFHMP, but the magnetic property of CFHMP/PTh composites is worse than that of CFHMP. At the thickness of 3.0 mm CFHMP/PTh composites exhibit strong electromagnetic dissipation ability (R-L = -33.8 dB at 9.5 GHz) and the absorption bandwidth (R-L < -10 dB) is 3.1 GHz (8.2-11.3 GHz). (C) 2017 Elsevier B.V. All rights reserved.