The invention discloses a fault diagnosis 
system and a fault diagnosis method based on sequence and 
consequence analysis of an 
event tree. The 
system comprises a 
data input module, an 
event tree resolution module, a fault tree preprocessing module, a 
fault tree analysis module and a diagram display module, wherein the 
data input module is used for acquiring reliability data and structure data of a given 
system, and storing the data in 
modes of a fault tree model and an 
event tree model; the event tree resolution module is used for 
processing the given event tree model and the fault tree model, 
processing a successful 
branch of the event tree with a respective 
substitution method, and constructing a traditional sequence fault tree model and a consequence fault tree model; the fault tree preprocessing module is used for preprocessing the given fault tree model; the 
fault tree analysis module is used for performing fault mode analysis, probability computation, importance computation, sensitivity computation and 
uncertainty analysis on the given fault tree model; and the diagram display module is used for displaying a 
fault analysis result of the given system in a diagram form. The system and the method can accurately construct sequence and consequence fault trees, and perform various approximate computation and accurate computation on the successful 
branch of each function event of the event tree, so that the reliability is improved.