On account of the influence of human activities and climate change, the variation of hydrological time series may occur in a basin. According to the principle of long-range dependence analysis of time series based on Hurst coefficient, as well as the R/S analysis method and the fractional Brownian motion theory, a hydrological variation analysis method was proposed, which could identify and test the variation of time series and its degree on the whole, i.e. no variation (weak variation), moderate variation,...