With the goal of lightweight and strong microwave absorption, polyaniline/aminopropyltriethoxysilane/silicon carbide (PANI/APTES/SiC) nano-composites with hierarchical architecture were fabricated through a facile in situ polymerization method. Herein, the SiC powders were modified with APTES in advance to achieve a more uniform envelope by PANI. The composites with different thicknesses of PANI layer and adjustable dielectric properties can be obtained by altering the PANI ratio. For the optimized sample, the minimum value of reflection loss is -51.34dB at 13.92GHz with a thickness of 1.9mm and the effective attenuation bandwidth is in a broad range from 12.19 to 17.45GHz (bandwidth of 5.26GHz). The outstanding absorption properties are closely related to the suitable impedance matching and the multiple loss mechanisms.