The invention relates to a flow similarity analysis method and device and provides a method for better analyzing hydrological process similarity. The method comprises steps as follows: the reversing times of a first flow hydrograph are determined; fractal dimensions of the first flow hydrograph are calculated; the similarity distance between the first flow hydrograph and a second flow hydrograph is determined according to the reversing times and the fractal dimensions, wherein the similarity distance is used for indicating similarity between the first flow hydrograph and the second flow hydrograph.