Abstract: With the "public transportation" operation of intercity railway, the railway platform door control system has become an important protection equipment to ensure the safety of passengers during boarding and alighting. In order to reduce the potential risk of platform door control system and improve the level of daily operation and maintenance, this articleused the Fault Tree Analysis (FTA) method to study the risk analysis and fault diagnosis of platform door control system. Based on the analysis of platform door control principle, the article used the HAZOP method to obtain the safety function of platform door, selected the function that platform door cannot be closed as the typical top event, used the down-line method to obtain the minimum cut set of fault tree, used the down-line method to get theminimum cut set of fault tree, constructed thefault tree of the event, and analyzed qualitatively and quantitatively it. The results show that the faults of platform door control system include optocoupler fault, inverter fault, motor sampling circuit fault and relay fault. The fault tree can provide auxiliary reference decision for the fault diagnosis of platform door control system, and has certain reference value for the optimal design of platform door control system.