Based on the current rapid development of electronic products, the development of light-weight, processable, environmentally friendly, long-life, durable, less corrosive, and tunable conductive composite materials with multiple applications may be the development direction of next-generation electronic devices. In this work, for the first time, we employed 3-Mercaptopropyltrimethoxysilane (3-MT) to modify viscose nonwovens and enhance the copper plating process. The prepared samples were characterized by Fourier transform infrared, Wide-angle X-ray diffraction (WAXD), scanning electron microscope + energy dispersive X-ray spectroscopy (SEM + EDS), thermogravimetric analysis (TGA), electrical resistivity, anti-corrosion, Joule heating, and electromagnetic interference (EMI) shielding. Results showed that 3-MT was covalently bound to the viscose surface through hydrolysis and condensation reactions and introduced SH groups. WAXD confirmed that the thiol modification did not change the internal crystal structure of viscose and copper ions. TGA and surface morphology analysis confirmed that the modified viscose promoted the deposition of metal particles in the copper plating process due to the affinity of thiol to metal so that copper particles almost completely wrapped the viscose fibers. In addition, 3MT@Cu@Viscose exhibits extremely low surface and volume resistivity (346.6 and 333.2 mΩ·m), improved corrosion resistance (corrosion rate reduced by 58% compared to the unmodified sample), fast Joule heating response (within 10 s) in low voltage (1 V) and excellent EMI shielding effectiveness (EMI SE > 50 dB). It showed great potential in future multi-functional electronic products such as electric heating sensors, smart clothing, and EMI shielding barrier.