Nowadays, there is a considerable demand for printable and functionalized thermoplastic polymer-based materials that are suitable for fused deposition modeling (FDM) three-dimensional (3D) printing. Hence, in this study, poly(vinyl alcohol) (PVA)/graphene nanoplate (GNP) multifunctional nanocomposites were thermally prepared for printing parts with enhanced electromagnetic interference (EMI) shielding capability via FDM. The related microstructure, processing parameters, and properties of the prepared PVA/GNP nanocomposite, as well as the printed parts, were accordingly investigated. The results indicated that ultrasonication realized the homogeneous dispersion of GNP fillers in the PVA matrix The added glycerol and GNP effectively destroyed the intrinsic hydrogen bonds of PVA through molecular complexation interaction, thus broadening the processing window of PVA and its nanocomposite. Additionally, the incorporation of GNP also facilitated the enhancement in the hydrophobicity of the nanocomposite. The mechanical properties, including Young's modulus, elongation at break, and ultimate tensile stress of the printed PVA/GNP parts, were optimized when the filling pattern was 0 X 0. Moreover, the EMI shielding efficiency (SE) of the printed PVA/GNP parts with a thickness of 2.43 mm reached 26-32 dB in the frequency range of 8-12.4 GHz, which can completely satisfy the requirements for practical applications. The corresponding EMI SE mechanism of the printed parts was also discussed.