This study explores the multi-physical field digital twin modeling and analysis of critical high-speed rail equipment. Based on the fundamental theories of electromagnetic fields, heat conduction, material mechanics, and fluid mechanics, mathematical models of coupled fields and three-dimensional finite element geometry models for key components of high-speed train high-voltage systems were established. For components such as onboard cable terminals, high-voltage disconnect switches, main circuit breakers, voltage transformers, and surge arresters, multi-physical field models, including electrothermal coupling and fluid-structure interaction, were constructed. Combined with actual operating parameters, comprehensive analyses of electric, thermal, stress, and flow fields were conducted. The results show that uneven electric field and temperature distributions inside the equipment may lead to local performance degradation or accelerated aging, which can be mitigated by optimized designs. Additionally, the use of digital twin technology allows for efficient and cost-effective data collection, enabling the identification of weak points, reliable fault diagnosis, and optimization of equipment design and maintenance strategies. This study holds significant value in enhancing operational reliability, extending service life, and ensuring the stability of high-speed rail systems, providing technical support for digitalized operation and maintenance.