Abstract: As the construction of China’s high-speed railway network continued to accelerate, the complexity of EMU maintenance operations increased, and there was an urgent need for intelligent auxiliary methods. Based on the two types of business requirements in EMU maintenance, namely training and operational assistance, this paper proposed an immersive auxiliary system for EMU maintenance operations that integrated Virtual Reality (VR) and Augmented Reality (AR) technologies. The paper used AR to provide intelligent guidance for on-site operations and VR to support simulated training and assessment, thereby constructing a closed-loop framework for improving maintenance capabilities called “training-practice-feedback-optimized training”. This system could provide technical support for enhancing maintenance efficiency and improving the skill level of maintenance personnel.