It is necessary to examine the characteristics of hydrological cycle in Gaoyou area of Jiangsu Province in response to climate change and flood disasters. In this study,121 atmospheric rain samples were collected and environmental factors were recorded from July 2015 to October 2017. We analyzed the hydrogen and oxygen stable isotopic composition of rain and identify moisture sources in this area. Results showed that the hydrogen and oxygen isotopic composition of rain had an seasonal variation,which was positive in the winter but negative in the summer. D-excess value was higher in winter than that in summer. On the annual scale,significantly negative relationships between deltaD (delta~(18)O) and temperature and between deltaD (delta~(18)O) and precipitation indicated theantitemperature effectandprecipitation amount effect,respectively. On the seasonal scale,there was no obvious temperature effectbut precipitation amount effectin autumn and winter. Results from the HYSPLIT model showed that the precipitation in this area came mainly from ocean evaporation that was influenced by the Chinese South Sea,Indian Ocean and Pacific Ocean. Precipitation in other seasons mainly came from the water vapor mixture from the Eurasian continent, Atlantic Ocean,Arctic Ocean,as well as local evaporation. The seasonal pattern of deltaD and delta~(18)O values in precipitation was mainly influenced by monsoon activity and El Nino-Southern Oscillation (ENSO). In addition,the precipitation isotopes clearly indicated the shift in climates from El Nino to La Nina.