As both Mann - Kendall and R/S methods are unable to get the past and future changing trends of the hydrological series independently,they are trialled to be combined herein. Aiming at the water resources data of Suzhou,the changing trend of the hydrological series therein is analyzed with the method of Mann - Kendall,while its fractal characteristics is obtained by R/S method for predicting the characteristics of the future trend of the water resources in Suzhou,and then the contribution ratios from the climate change and the human activity on the change of water resources are quantitatively evaluated with elastic coefficient method. The result shows that the volume of water resources in Suzhou presents an upward trend for both the past 60 years and the future; moreover,an abrupt change occurred in 1979. The climate change is main driving factor for the runoff change with the contribution ratio of over 87%,while contribution ratio from the human activity is only 13%. Mastering the changing trend of the water resources in Suzhou can provide the decision bases for both the reasonable development and utilization of water resources and the sponge city construction for Suzhou.