Abstract: This study takes the optimization and renovation project of the grounding grid of a 330 kV substation as an example, deeply exploring a comprehensive grounding grid optimization design that integrates "three-dimensional resistance reduction, surface potential equalization, and full-life anti-corrosion" and its application effects. Engineering verification shows that this solution has a significant effect on reducing grounding resistance, balancing surface potential, and improving anti-corrosion performance, achieving the expected safety and long-term operational goals. Measured data from the project indicates that the overall substation grounding resistance decreased from 0.518 Ω to 0.42 Ω, with a resistance reduction rate of 18.9%; the maximum step voltage difference dropped from 315 V to 158 V, meeting safety requirements; and the anti-corrosion system is operating effectively. Therefore, this study on the renovation of grounding grids in aged substations in areas with high soil resistivity can solve problems such as excessive grounding resistance, high step voltage difference, and severe conductor corrosion, and has certain practical significance in improving the safe operation level of substations.