Over the past two decades, China’s high-speed trains have advanced from a follower to a global leader, achieving the highest commercial operation speed, deploying the largest fleet of high-speed trains, recording the fewest failures per 100 km, and delivering the best running stability worldwide. High-speed trains have not only become a prominent symbol of national development, but also a vivid representation of equitable access to the benefits of modernization in the new era. The key to this remarkable success lies in the exceptional system integrity achieved in China’s high- speed trains. System integrity includes structural integrity, dynamic integrity, and functional integrity. This article defines the concept of system integrity and provides a comprehensive interpretation. Intelligent operation and maintenance of high-speed trains has emerged as a major research focus in recent years. Aiming to safeguard system integrity, this article explores intelligent operation and maintenance strategies, including dynamic condition monitoring and evaluation, intelligent service life prediction, and preventive maintenance planning.