This paper used the Lean watershed, the major tributary of Poyang lake basin as an example to analyze the dynamics of precipitation, temperature, storm events, drought and streamflow (1954-2012). The Sliding Average Method and Mann- Kendall test were used for this study. Results showed that the annual mean temperature increased significantly (P＜0.01)，in the past decades, the drought days was increasing, especially in the 2003(56d), 2004(57d) and 2007(81d) year; evaporation showed a reducing trend；besides,the average intensity and frequency of storm rainfall were increased. Through the Mann-Kendall mutation point test, two breakpoints in the runoff (year 1985 and year 2003) were detected in the Le'an River Watershed. All above results clearly demonstrate that there are increased trend in storm intensity and the duration of drought, which may have the risk of flood and drought in the future. Therefore, integrated watershed management strategies should be made to minimize the effects of climate change on water resources.