Abstract: To standardize and enhance the efficiency of transformer differential protection system commissioning, a virtual simulation-based optimization framework has been developed. Taking the Jiuduntan 330 kV substation expansion project as a case study, this research establishes a closed-loop mechanism covering pre-commissioning, on-site joint debugging, and abnormal condition simulation. A virtual simulation platform has been designed to simulate analog/switching signals, validate secondary circuit logic, and perform parameter snapshot comparison with waveform analysis. Results demonstrate that the new process outperforms traditional methods in commissioning duration, fault coverage, criterion accuracy, and data archiving integrity, showcasing significant engineering applicability and promotion potential.