Train communication network (TCN) is an important guarantee for the reliable and safe operation of high-speed rail train. The higher reliability of the TCN is, the safer operation of high-speed rail train will be, and the cost of overhaul and maintenance will be greatly reduced. The 250 km/h high-speed rail TCN being developed in China is the first time that the train communication Ethernet (TCE) is used as train control network. Therefore, it is of great practical significance to analyze the reliability of TCE and improve the reliability of TCN design and vehicle design. Dynamic fault tree (DFT) and fault Petri nets (FPN) are both important methods for system reliability analysis. Among them, DFT is most widely used in the field of engineering analysis. The FPN method also has its unique characteristics and advantages, which can describe fault propagation analysis and dynamic transition process in practical application. In this paper, TCE's structure, working principle, and fault mode are analyzed to sort out the relationship between complex fault events and establish a DFT with TCE failure as the top event. DFT and FPN methods were combined to better express the dynamic propagation of TCE fault and carry out the fault probability evaluation and system reliability based on the known prior failure rate. The analysis results show that improving the reliability of specified network segments of TCE is of great help to improve the reliability of the high-speed rail train.