Abstract: The cause of typical faults in Shanghai Rail Transit Line 2 signal data transmission system is analyzed, targeting which specific fault treatments are proposed and maintenance countermeasures are summarized. There are measures that can effectively improve the safety, reliability and operation stability of signal data transmission system, such as turning on the internet storm suppression function of MOXA exchanger, optimizing internet configuration structure, upgrading terminal server hardware, and reinforcing monitoring on central H3C internet management system.