This study can help know water vapor transports and moisture cycle of Nanjing area. Based on the data of the hydrogen and oxygen stable isotopes in precipitation in Nanjing provide by the Global Network of Isotopes in Precipitation (GNIP) and the meteorological statistics, the temporal variations of stable isotopes in precipitation and their influencing factors were analyzed and the Local Meteoric Water Line (LMW L) was established. The results were as follows: δ18 O value was high in spring and low in summer. As to the annual scale, the relationship between δ18O in precipitation and temperature was not positive correlated, δ18O was negative related to precipitation amount. To the seasonal scale, positive correlationship was found for temperature and precipita tion amount only in winter. The water vapor source of Nanjing was tracked by HYSPLIT model, the modeled trajectory of vapor source indicated that the variation of stable isotopes was influenced by Asian summer, winter monsoon and its vapor.