Abstract: In order to ensure the safety of the high-speed railway operating environment and meet the business needs of train over-the-horizon applications, this paper designed an over-the-horizon ground system for high-speed railway train. The paper utilized key technologies such as unified data access, video compression and processing, over-the-horizon correlation matching algorithms, and secured data transmission to implement functions such as over-the-horizon data access and processing, over-the-horizon correlation, and operation and maintenance management, assisted in the early prediction and disposal of sudden emergencies. The results of the actual train test on the Beijing-Zhangjiakou high-speed railway show that the system meets the design expectations, operates stably for a long time, and can provide technical support for the safe operation of high-speed trains.