<p>Hydrogen diffuses and accumulates at grain boundaries and stress concentration zones in materials, leading to degradation of electrical properties and affecting the safe service of key components in nuclear power systems. This study investigates the effects and mechanisms of hydrogen on the electrical properties of 316L stainless steel through experiments and numerical simulations. Specimens with varying hydrogen content were prepared via electrochemical charging, and their electrical conductivity was measured using the four-point probe method. The results show that the uncharged sample has a resistivity of 0.703 μΩ·m and a conductivity of 1.43×10⁶ S/m, consistent with the typical properties of 316L stainless steel. As the hydrogen charging time increases from 12 to 36 h, the resistivity significantly rises to 0.87 μΩ·m, and the conductivity decreases to 1.15×10⁶ S/m. The changes are more pronounced in the early stage of charging, and a linear relationship is observed between hydrogen content and both resistivity and conductivity. Finite element simulations of hydrogen diffusion at the crack tip and its coupling with the stress field reveal that external loading induces hydrogen accumulation in high-stress regions, resulting in locally reduced conductivity. This study provides new insights for hydrogen damage monitoring and service life prediction of nuclear power materials.</p>