Abstract: With the increasing scale of power grids and the growing intensity of lightning, the safety of substation lightning protection and grounding systems has become a critical factor affecting the stable operation of power systems. To address the limitations of traditional grounding design, which fails to effectively quantify risks and adapt to complex geological environments, this paper proposes a lightning protection and grounding method for substations based on risk assessment. By establishing a lightning current distribution density model and a dynamic ground potential rise equation, and combining risk quantification with sensitivity analysis, the proposed method achieves refined evaluation and optimization of grounding system safety. Finally, verification on a substation test platform demonstrates that the method effectively reduces lightning risk, enhances potential equalization performance, and provides theoretical guidance and engineering reference for the design of lightning protection and grounding systems.