A fault tree is established based on structural analysis, working principle analysis, and failure mode and effects analysis (FMEA) of the pantograph-type current collector on the Chinese Rail High-Speed Electric Multiple Unit (CRH EMU) train. To avoid the deficiencies of fault tree analysis (FTA), Petri nets modelling is used to address the problem of data explosion and carry out dynamic diagnosis. Relational matrix analysis is used to solve the minimal cut set equation of the fault tree. Based on the established state equation of the Petri nets, initial tokens and enable-transfer algorithms are used to express the fault transfer process mathematically and improve the efficiency of fault diagnosis inferences. Finally, using a practical fault diagnosis example for the pantographs on CRH EMU trains, the proposed method is proved to be reasonable and effective.