Clearance is one of the core elements of insulation coordination for automotive electrical equipment, directly determining the insulation reliability and operational safety of vehicle electrical systems. Based on domestic and international automotive electrical safety standard systems, this paper analyzes the design principles, key influencing factors, and specification requirements of clearance, and focuses on expounding the mechanism by which factors such as rated voltage, overvoltage category, and on-board pollution degree affect the determination of clearance, aiming to provide technical support for the design, manufacturing, testing, and certification of automotive electrical equipment.