The R/S analysis is known as Rescale Range Analysis. The method is used to study the various laws of statistic by changing the time range and analyze the law similarity between integrate and parts. This paper analyzed and forecast the future landslides frequency and trend by R/S method, based on the past landslide data. Moreover, the analysis and forecast could dynamically evaluate the area landslide danger degree. According to the landslide data of Wanzhou in the Three Gorges Reservoir, the time records and Hurst index of the different landslide sizes were studied in the different time extensions. According to the Hurst indexes, this method forecasted the maximum fluctuate extension of landslide number in the 5 years. The relationship between time correlation function and Hurst indexes was acquired by Fractional Brownian Motion. The relationship could forecast quantifiably for the development trend of area landslides. The results showed that the frequency forecast of area landslides could dynamically evaluate the area landslide danger degree.