Abstract: To enhance the commissioning accuracy and operational reliability of the main network protection system in digital substations, this paper, based on the IEC 61850 standard and the concept of modular commissioning, proposes a systematic commissioning framework of "quantified core indicators - key technology breakthroughs - engineering performance verification." By optimizing sampling synchronization compensation, SV/GOOSE message parsing, dynamic fault simulation, and device coordination techniques, precise commissioning under multi-dimensional coupled scenarios is achieved. The study shows that this framework can efficiently complete main network protection commissioning, ensuring a 100% protection action correctness rate. In engineering applications, the system demonstrated continuous and stable operation, providing strong support for reliable commissioning of main network protection in digital substations.