Abstract: With the rapid development of high speed railway and constant expansion of communications network scale,a higher requirement for the reliability of network communication is put forward. To reduce or avoid the impact of the accident, quick detection, accurate diagnosis and faults elimination are required to improve the safety and reliability of the system. According to the characters of fault, a new method to solve the fault diagnosis based on the traditional Petri net was proposed, which was applied in the fault diagnosis fields for railway communication.

Key words: Petri net, fault diagnosis, high speed railway communication