Abstract: This paper focuses on the commissioning technology of smart substations based on secondary circuit comparison. Using case analysis, it explores the characteristics differences of various secondary circuits as a starting point and emphasizes the necessity of commissioning work. The paper outlines key commissioning points, including differential parameter verification, dynamic response testing, and collaborative performance optimization. It also presents technical solutions for suppressing circuit interference discrepancies and ensuring inter-circuit information security. Based on project field data, the study confirms that this technology can accurately identify hidden risks across circuits, keeping parameter deviations, coordination errors, and other factors within safe limits, thus supporting the safe and stable operation of smart substations.