A fault analysis method includes: using a matrix of two sets of microgrid power distribution networks to analyze and solve a fault current, and for various types of faults of the distributed power distribution system, obtaining appropriate boundary conditions to calculate a variety of different types of single or simultaneous fault currents of load points. The present invention may be further applied to a situation where a bus or impedance or parallel loop is added. The present invention has good robustness and execution speed, and requires small memory space for calculation of analysis and identification of a power flow fault of the distributed power distribution system, and may be actually applied to an instrument control system for identification and analysis of a fault of a large-scalemicrogrid distribution system.