Abstract: Periodicity and long-range correlation are two important characteristics of the evolution and fluctuation of runoff series. This study took the natural runoff sequences over the period of 1956-2001 at three hydrologic stations (Yangjiaping, Yuluoping and Zhangjiashan) in the Jinghe Watershed as research objects. The power spectrum method and the detrended fluctuation analysis were employed to analyze the natural runoff sequences at the three stations. Results demonstrate that all of the natural runoff sequences from the three stations are“white noise”processes. Under the 0.05 confidence level, there exists a prominent period of 2.2 years for the natural sequences from the three stations. There is a good correlation between the runoff series and the precipitation. The natural runoff sequences at the three stations have the same scale invariant interval (the variable τ is between 6 and 30 months). The related scaling exponents α are greater than 0.5 (0.5493 for Zhangjiashan Station, 0.5552 for Yuluoping Station, and 0.5549 for Yangjiaping Station), which shows that there is long-range correlation or persistence of the natural runoff at the three stations. The long-range correlation may associate with the formation of 2.2-year prominent period of natural runoff sequences.