Abstract: The level crossing is the intersection of highway and railway, and it is also the prone accident point. Aiming at the safety critical characteristics of the level crossing, this paper studied the fault diagnosis method of the level crossing signal equipment, took Petri Net as a tool, modelled the control logic and process of the level crossing signal equipment, used TINA simulation software to generate the reachable graph of the level crossing signal equipment model, and implemented the fault diagnosis of the level crossing signal equipment. The application of this fault diagnosis method would help to improve the safety and operation efficiency of level crossings.