The present invention provides a power system state similarity analysis method. The method comprises the steps of determining the stage number of the multistage topology analysis through network analysis and calculation, subjecting the member of a rule set F determined according to the stage of the topology analysis to topology analysis, extracting the key information out of an abstract result of the multistage topology analysis so as to form state vectors, and determining the similarity between states according to the distances of different state vectors calculated according to a distance function. According to the technical scheme of the power grid status data similarity analysis method, the similarity between different power grid states can be quickly quantized.