The modified Fe₃O₄@Graphene (mG1F1) composites with different contents was added as a variable, and analyze the influence of mG1F1 content on the electromagnetic shielding efficiency of composite coatings to prepare wood-based composites with better electromagnetic shielding performance. The results showed that with the increasing of mG1F1 content, the coatings morphology of wood surface tended to be smooth. When the amount of mG1F1 was 200 mg, the surface roughness was the smallest (12.730 μm). When the additive amount of mG1F1 was 400 mg, the conductivity was up to 1429 S/cm. The XRD demonstrated that there was a clear difference between the five-fold ratio of G1F1 and the normal ratio of mG1F1, and the diffraction peak intensity of single layer graphene of quintuple ratio composite decreased significantly. When the content of mG1F1 was 200 mg, the composite coatings had the best hydrophobicity and the contact angle was 122.0°. Herein, the electromagnetic shielding efficiency in the range from 0.03 to 3000 MHz can reach 91.60 dB, which demonstrated the composite materials can shield 99% of electromagnetic waves.