In this work, enhanced electromagnetic wave adsorption performance was observed in the engineered polyaniline (PANI)/epoxy nanocomposites reinforced by the PANI fillers. The PANI spheres (PANI-S) and PANI fibers (PANI-F) were prepared by the chemical oxidation polymerization method and interface polymerization method, respectively. The characterizations including scanning electron microscopy, Fourier transform infrared spectra, and X-ray diffraction were applied to analyze the morphology, chemical and crystal structures of PANI filler. The reflection loss of PANI/epoxy with a mixture of PANI-F and PANI-S can reach -36.8 dB at 17.7 GHz, due to the synergistic effect of PANI fillers with different geometries. Meanwhile, the mechanical properties (including tensile strength, toughness and flexural strength) of PANI/epoxy were also studied. This work would provide the guideline for the preparation of engineered epoxy nanocomposites for electromagnetic wave pollution treatment.